ARTICLE | doi:10.20944/preprints202106.0673.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Trypanosoma cruzi; Presenilin; Nicastrin; γ-secretase; transmembrane motif; B-cell epitope; Spot synthesis; type I transmembrane glycoprotein; vesicular trafficking; flagellar pocket
Online: 28 June 2021 (14:55:42 CEST)
Nicastrin (NICT) is a transmembrane protein physically associated with the polytypical aspartyl protease presenilin that plays a vital role in the correct localization and stabilization of presenilin to the membrane-bound γ-secretase complex. This complex is involved in the regulation of a wide range of cellular events including cell signaling and the regulation of endocytosed membrane proteins for their trafficking and protein processing. Mehtods: In Trypanosoma cruzi, the causal agent of the Chagas disease, an NICT-like protein (Tc/NICT) was identified with a short C-terminus orthologous to the human protein, a large ectodomain (ECD) with numerous glycosylation sites and a single core transmembrane domain containing a putative TM-domain (457GSVGA461) important for the γ-secretase complex activity. Results: Using the Spot-synthesis strategy with Chagasic patient sera, five extracellular epitopes were identified and synthetic forms were used to generate rabbit anti-Tc/NICT polyclonal serum that recognized a ~72-kDa molecule in immunoblots of T. cruzi epimastigote extracts. Confocal microscopy suggests that Tc/NICT is localized in the flagellar pocket, which is consistent with data from our previous studies with a T. cruzi presenilin-like protein. Phylogenetically, Tc/NICT was localized within a subgroup with the T. rangeli protein that are clearly detached from the other Trypanosomatidae such as T. brucei. These results, together with a comparative analysis of the selected peptide sequence regions between the T. cruzi and mammalian proteins suggest a divergence from the human NICT that might be relevant to Chagas disease pathology. As a whole, our data show that an NICT-like protein is expressed in the infective and replicative stages of T. cruzi and may be considered further evidence for a γ-secretase complex in trypanosomatids.
COMMUNICATION | doi:10.20944/preprints202008.0665.v1
Subject: Biology And Life Sciences, Virology Keywords: SARS-CoV-2; envelop protein; mutations; transmembrane domain; triple cysteine motif
Online: 30 August 2020 (11:50:59 CEST)
The ongoing mutations in the structural proteins of SARS-CoV-2 is the major impediment for prevention and control of the COVID-19 disease. The envelope (E) protein of SARS-CoV-2 is a structural protein existing in both monomeric and homopentameric forms, associated with a multitude of functions including virus assembly, replication, dissemination, release of virions, infection, pathogenesis, and immune response stimulation. In the present study, 81,818 high quality E protein sequences retrieving from the GISAID were subjected to mutational analyses. Our analysis revealed that only 0.012 % (982/81818) stains possessed amino acid (aa) substitutions in 63 sites of the genome while 58.77% mutations in the primary structure of nucleotides in 134 sites. We found the V25A mutation in the transmembrane domain which is a key factor for the homopentameric conformation of E protein. We also observed a triple cysteine motif harboring mutations (L39M, A41S, A41V, C43F, C43R, C43S, C44Y, N45R) which may hinder the binding of E protein with spike glycoprotein. These results therefore suggest the continuous monitoring of each structural protein of SARS-CoV-2 since the number of genome sequences from across the world are continuously increasing.
REVIEW | doi:10.20944/preprints202005.0222.v1
Subject: Biology And Life Sciences, Cell And Developmental Biology Keywords: myelin; myelination; development; peripheral neuropathies; protein folding; transmembrane protein; protein-membrane interaction; protein-protein interaction
Online: 13 May 2020 (04:51:20 CEST)
Myelin protein zero (P0), a type I transmembrane protein, is the most abundant protein in peripheral nervous system (PNS) myelin – the lipid-rich, periodic structure that concentrically encloses long axonal segments. Schwann cells, the myelinating glia of the PNS, express P0 throughout their development until the formation of mature myelin. In the intramyelinic compartment, the immunoglobulin-like domain of P0 bridges apposing membranes together via homophilic adhesion, forming a dense, macroscopic ultrastructure known as the intraperiod line. The C-terminal tail of P0 adheres apposing membranes together in the narrow cytoplasmic compartment of compact myelin, much like myelin basic protein (MBP). In mouse models, the absence of P0, unlike that of MBP or P2, severely disturbs the formation of myelin. Therefore, P0 is the executive molecule of PNS myelin maturation. How and when is P0 trafficked and modified to enable myelin compaction, and how disease mutations that give rise to incurable peripheral neuropathies alter the function of P0, are currently open questions. The potential mechanisms of P0 function in myelination are discussed, providing a foundation for the understanding of mature myelin development and how it derails in peripheral neuropathies.
ARTICLE | doi:10.20944/preprints202301.0221.v1
Subject: Computer Science And Mathematics, Artificial Intelligence And Machine Learning Keywords: Ion channels; Membrane proteins; Transmembrane proteins; Drug discovery; Protein language models; Convolutional Neural Network
Online: 12 January 2023 (09:21:08 CET)
Ion channels are integral membrane proteins that facilitate the movement of ions across cell membranes, playing a key role in a range of biological processes. The high cost and time required for wet lab experiments to characterize ion channels has spurred the development of computational methods for this purpose. In our previous work, we demonstrated the effectiveness of protein language models for ion channel prediction, using a logistic regression classifier to distinguish ion channels from non-ion channels (TooT-BERT-C) and transporters from non-transporters (TooT-BERT-T). In this study, we build upon this approach by using a combination of classical machine learning classifiers and a Convolutional Neural Network (CNN) with fine-tuned representations from ProtBERT, ProtBERT-BFD, and MembraneBERT to discriminate ion channels from non-ion channels. The results of our experiments demonstrate that TooT-BERT-CNN-C, a combination of the representations from ProtBERT-BFD and a CNN, outperforms existing state-of-the-art methods for predicting ion channels, with a Matthews Correlation Coefficient (MCC) of 0.86 and an accuracy of 98.35% on an independent test set.
REVIEW | doi:10.20944/preprints201711.0007.v1
Subject: Biology And Life Sciences, Virology Keywords: human papillomavirus; HPV16; L2; subcellular trafficking; mitosis; transmembrane domain; translocation; membrane penetration; toxin; fusion peptide; gamma secretase; retromer
Online: 1 November 2017 (05:05:31 CET)
Beginning in 2012, our understanding of human papillomavirus (HPV) subcellular trafficking has undergone a drastic paradigm shift. Work from multiple laboratories has revealed that HPV has evolved a unique means to deliver its viral genome (vDNA) to the cell nucleus, relying on a myriad of host cell proteins and processes. The major breakthrough finding from these recent endeavors was the realization of L2-dependent utilization of cellular sorting factors for the retrograde transport of vDNA away from degradative endo/lysosomal compartments to the Golgi, prior to mitosis-dependent nuclear accumulation of L2/vDNA. An overview of current models of HPV entry, subcellular trafficking, and the role of L2 during initial infection is provided below, highlighting unresolved questions and gaps in knowledge.
ARTICLE | doi:10.20944/preprints202109.0503.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: mitogenome; transmembrane proteins; substitution matrix; JTT matrix; molecular evolution; partitioned models; mixture models; RY coding; cyto-nuclear discordance
Online: 29 September 2021 (16:57:38 CEST)
Phylogenomic analyses have revolutionized the study of biodiversity, but they have revealed that estimated tree topologies can depend, at least in part, on the subset of the genome that is analyzed. For example, estimates of trees for avian orders differ if protein coding or non-coding data are analyzed. The bird tree is a good study system because the historical signal for relationships among orders is very weak, which should permit subtle non-historical signals to be identified, while monophyly of orders is strongly corroborated, allowing identification of strong non-historical signals. Hydrophobic amino acids in mitochondrially-encoded proteins, which are expected to be found in transmembrane helices, have been hypothesized to be associated with non-historical signals. We tested this hypothesis by comparing the evolution of transmembrane helices and extramembrane segments of mitochondrial proteins from 420 bird species, sampled from most avian orders. We estimated amino acids exchangeabilities for both structural environments and assessed the performance of phylogenetic analysis using each data type. We compared those relative exchangeabilities with values calculated using a substitution dataset for transmembrane helices from a variety of sampled set of nuclear- and mitochondrially-encoded proteins, allowing us to compare the bird-specific mitochondrial models with a general model of transmembrane protein evolution. To complement our amino acid analyses, we examined the impact of protein structure on patterns of nucleotide evolution. Models of transmembrane and extramembrane sequence evolution for amino acids and nucleotides exhibited striking differences, but there was no evidence for strong topological data type effects. However, incorporating protein structure into analyses of mitochondrially-encoded proteins improved model fit. Thus, we believe that considering protein structure will improve analyses of mitogenomic data, both in birds and in other taxa.
ARTICLE | doi:10.20944/preprints201901.0232.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: protein function, mtORF, Stylophora, thermal adaptation, disordered amino acids residues, pocilloporid corals, a transmembrane protein, pocilloporid corals.
Online: 23 January 2019 (08:58:41 CET)
More than a decade ago, a new mitochondrial Open Reading Frame (mtORF) was discovered in corals of the family Pocilloporidae, which turn out to be an effective barcode gene for these corals. However, its function remains unknown. Recently, this gene revealed the existence of a hybrid Stylophora lineage (RS_LinA) inhabiting in sympatry along the environmental gradient of the Red Sea (18.5°C to 33.9°C) with its parental species (RS_LinB). Furthermore, in RS_LinB, the mtORF uncovered phylogeographic patterns that were strongly correlated with environmental variations. This was similar to the patterns unraveled by hsp70, suggesting that mtORF too might be involved in thermal adaptation. Here we used computational approaches to characterize the mtORF and to identify its potential role. Results showed that this gene encodes a transmembrane protein (0.97<P< 1.00) involved in transport (0.80<P< 0.87), regulation of metabolic processes (0.70<P<0.85), and likely in the cell-surface receptor signaling pathway (0.56<P<0.80). Predicted protein functions differed among Stylophora lineages and interestingly, in RS_LinB only, the protein was intrinsically disordered and displayed domains involved in cellular complexes and stress response (0.0001< P <0.001). These characteristics, exclusive of an endemic lineage adapted to extreme environmental fluctuations, support a role of the mtORF in stress response, speciation and adaptation.
REVIEW | doi:10.20944/preprints202304.0901.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: PCa; taxanes-based drugs; combination therapy; transmembrane proteins
Online: 25 April 2023 (08:34:03 CEST)
The oncologic disease is a big global health issue that causes thousands of deaths annually, and it has a significant impact in the life quality of patients. Prostate cancer (PCa) is the second most diagnosed cancer and the fourth leading cause of cancer-related death in men in the western world. Delineation of pathogenetic pathways and key driver molecular alterations involved in PCa development has provided a roadmap for the evaluation of biomarkers in predicting disease outcome and to identify potential therapeutic targets. Chemotherapeutic agents introduced from the 1990s include the taxanes (paclitaxel, docetaxel and cabazitaxel), which are the most anticancer drugs used for PCa treatment. This review presents the current knowledge about the onset and development of PCa, state-of-art on the use of taxane-based therapy, and their combination with targeting different transmembrane oncoproteins in PCa. The silencing of some transmembrane proteins can improve taxane sensitivity, and therefore, may be a mechanism to improve the ef-fectiveness of these drugs in PCa treatment. This combined therapy needs to be explored as po-tential therapeutic agent for reducing cell proliferation, migration, and invasiveness in PCa.
ARTICLE | doi:10.20944/preprints202208.0302.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Verticillium wilt; cotton; transmembrane protein; resistance; plant immunity
Online: 17 August 2022 (05:28:04 CEST)
Verticillium wilt (VW) is a soil borne fungal diseases caused by Verticillium dahliae Kleb, and lead to serious damage to cotton production annually in the world. In our previous study, a transmembrane protein 214 protein (TMEM214) gene associated with VW resistance was map-based cloned from Gossypium barbadense (G. barbadense). TMEM214 proteins are a kind of transmembrane protein, but their function in plants is rarely studied. To reveal the function of TMEM214s in VW resistance, all six TMEM214s were cloned from G. barbadense in this study. These genes were named as GbTMEM214-1, GbTMEM214-4 and GbTMEM214-7 according to their location on the chromosomes, and the encoded proteins are all located on cell membrane. TMEM214 genes were all induced by Verticillium dahliae inoculation and showed significant differences between resistant and susceptible varieties, but the expression patterns of GbTMEM214s under different hormone treatments were significantly different. Virus-induced gene silencing analysis showed the resistance to VW of GbTMEM214s-silenced lines decreased significantly, which further proves the important role of GbTMEM214s in the resistance to Verticillium dahliae. Our study provides an insight into the involvement of GbTMEM214s in VW resistance, which was helpful to better understand the disease resistance mechanism of plants.
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: MIF; Lingulodinium polyedra; transmembrane protein; dinoflagellate; stress response; secretion
Online: 11 July 2020 (17:23:36 CEST)
Macrophage Migration Inhibitory Factors (MIF) are pivotal cytokines/chemokines for vertebrate immune systems. MIFs are typically soluble single-domain proteins that are conserved across plant, fungal, protist, and metazoan kingdoms but their functions have not been determined in most phylogenetic groups. Here we describe an atypical multidomain MIF protein. The marine dinoflagellate Lingulodinium polyedra produces a transmembrane protein with an extra-cytoplasmic MIF domain, which localizes to cell wall-associated membranes and vesicular bodies. This protein is also present in the membranes of extracellular vesicles accumulating at the secretory pores of the cells. Upon exposure to biotic stress, L. polyedra exhibits reduced expression of the MIF gene and reduced abundance of the surface-associated protein. These findings indicate that the transmembrane MIF may contribute to intercellular communication and/or interactions between free-living organisms in multispecies planktonic communities and raise the question of possible analogies in MIF functions between cells of metazoan organisms and protist communities.
ARTICLE | doi:10.20944/preprints202107.0540.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: polymeric spiral-wound membrane; microfiltration; transmembrane pressure; diafiltration; micellar casein concentrate
Online: 23 July 2021 (11:05:17 CEST)
Micellar Casein Concentrate (MCC) is manufactured from microfiltration (MF) of skim milk utilizing ceramic or polymeric membrane filtration. While ceramic filtration has higher efficiency, use of polymeric is cost effective and the process is familiar to several US dairy processors. The aim of the present study was to develop an optimized membrane filtration process to produce MCC using spiral wound polymeric membrane filtration (SW MF) system by systematic selection of transmembrane pressure (TMP) and level of diafiltration (DF). Using skim milk as feed material, preliminary lab-scale MF experiments were conducted using 0.5 µm polyvinylidene fluoride (PVDF) membrane. Three TMP (34.5, 62.1, and 103.4 kPa) and three levels of DF (70, 100, and 150%) along with a process without DF as control were used in the study. Effect of TMP and effectiveness of DF on flux rates, SP removal, casein to total protein (CN/TKN) ratio, casein to true protein (CN/TP) ratio, rejection of casein (rej CN) and SP (rej SP) were evaluated. At all TMP values used in the study, the overall flux (O Flux) increased with the level of DF. Highest O Flux of 30.77 liter per meter square per hour (LMH) was obtained with 34.5 kPa pressure and 150% DF. The impact of DF was more pronounced at lower pressures than at the higher pressures used in the study. With controlled DF, instantaneous flux was maintained within 80% of initial flux for the entire process run. For all the experiments, casein has a rejection of 0.97 to 1.0, while serum protein has the lowest rejection of 0.10 at 34.5 kPa pressure and 150% DF level. Use of 34.5 kPa and DF level of 150 % contributed to 81.45% SP removal, and casein to true protein ratio of 0.96. SP removal data from the lab-scale experiments were fitted into a mathematical model using DF and square of TMP as factors. The model predicts SP removal within 90-95% of actual SP removal got from the pilot plant experiments.
REVIEW | doi:10.20944/preprints202305.1788.v1
Subject: Biology And Life Sciences, Endocrinology And Metabolism Keywords: adipose tissue; corin; hepsin; matriptase-2; type II transmembrane serine protease; thermogenesis
Online: 25 May 2023 (09:51:58 CEST)
Adipose tissue is a crucial organ in energy metabolism and thermoregulation. Adipose tissue phenotype is controlled by various signaling mechanisms under pathophysiological conditions. Type II transmembrane serine proteases (TTSPs) are a group of trypsin-like enzymes anchoring on the cell surface. These proteases act in diverse tissues to regulate physiological processes, such as food digestion, salt-water balance, iron metabolism, epithelial integrity, and auditory nerve development. More recently, several members of the TTSP family, namely, hepsin, matriptase-2, and corin, have been shown to play a role in regulating lipid metabolism, adipose tissue phenotype, and thermogenesis, via direct growth factor activation or indirect hormonal mechanisms. In mice, hepsin deficiency increases adipose browning and protects from high-fat diet-induced hyperglycemia, hyperlipidemia, and obesity. Similarly, matriptase-2 deficiency increases fat lipolysis and reduces obesity and hepatic steatosis in high-fat diet-fed mice. In contrast, corin deficiency increases white adipose weights and cell sizes, suppresses adipocyte browning and thermogenic responses, and causes cold intolerance in mice. These findings highlight an important role of TTSPs in modifying cellular phenotype and function in adipose tissue. In this review, we provide a brief description about TTSPs and discuss recent findings regarding the role of hepsin, matriptase-2, and corin in regulating adipose tissue phenotype, energy metabolism, and thermogenic responses.
REVIEW | doi:10.20944/preprints202307.0552.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: cancer chemotherapy; transmembrane receptors; EGFR; targeted protein degradation; furfuryl-quinolin-triazole-thiol chemicals
Online: 10 July 2023 (07:23:13 CEST)
Targeted protein degradation is an attractive technology for cancer treatment due to its ability to overcome the unpredictability of small molecule inhibitors that cause resistance mutations. In recent years, various targeted protein degradation strategies have been developed based on the ubiquitin-proteasome system in the cytoplasm or the autophagy-lysosomal system during endocytosis. In this review, we describe and compare technologies for targeted inhibition and targeted degradation of the epidermal growth factor receptor (EGFR), one of the major proteins responsible for the onset and progression of many types of cancer. In addition, we have developed an alternative strategy, called alloAUTO, based on the binding of new heterocyclic compounds to an allosteric site located in close proximity to the EGFR catalytic site. These compounds cause targeted degradation of the transmembrane receptor, simultaneously activating both systems of protein degradation in cells. Damage to EGFR signaling pathways promotes inactivation of Bim sensor protein phosphorylation, which leads to disintegration of the cytoskeleton, followed by detachment of cancer cells from the extracellular matrix and, ultimately, to cancer cell death. This hallmark of targeted cancer cell death suggests an advantage over other targeted protein degradation strategies, namely that the fewer cancer cells survive, the fewer chemotherapy-resistant mutants appear.
ARTICLE | doi:10.20944/preprints202010.0346.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Trypanosoma cruzi; Presenilin; aspartic protease; SPOT-synthesis; anti-peptide antibodies; immunolocalization; transmembrane domains
Online: 16 October 2020 (12:01:25 CEST)
The increasing detection of infections of Trypanosoma cruzi, the etiological agent of Chagas disease, in non-endemic regions beyond Latin America has risen to be a major public health issue. With an impact in the millions of people, current treatments rely on antiquated drugs that produce severe side effects and are considered nearly ineffective for the chronic phase. The minimal progress in the development of new drugs highlights the need for advances in basic research on crucial biochemical pathways in T. cruzi to identify new targets. Here, we report on the T. cruzi presenilin-like transmembrane aspartyl enzyme, a protease of the aspartic class in a unique phylogenetic subgroup with T. vivax separate from protozoans. Computational analyses suggests it contains 9 transmembrane domains and an active site with the characteristic PALP motif of the A22 family. Multiple linear B-cell epitopes were identified by SPOT synthesis analysis with Chagasic patient sera. Two were chosen to generate rabbit antisera, whose signal was primarily localized to the flagellar pocket, intracellular vesicles and endoplasmic reticulum in parasites by whole cell immunofluorescence. The results suggest that the parasitic presenilin-like enzyme could have a role in the secretory pathway and serve as a biomarker for infections.
ARTICLE | doi:10.20944/preprints202311.0509.v1
Subject: Medicine And Pharmacology, Medicine And Pharmacology Keywords: CFTR; cystic fibrosis; cystic fibrosis transmembrane conductance regulator; docking; molecular dynamics; curcumin; CFTR modulators
Online: 8 November 2023 (04:12:50 CET)
Curcumin, a major constituent of turmeric, has beneficial effects against several diseases. In cystic fibrosis (CF), this compound potentiates the activity of a number of cystic fibrosis transmembrane conductance regulator (CFTR) mutants. Despite holding promise in the treatment of CF, the curcumin binding site in CFTR and the molecular mechanism of activation of this channel are still unknown. The results of the study, based on docking and molecular dynamics (MD) simulations, allow to propose that curcumin binds the closed ATP-free CFTR near the NBD1/ ICl1/ICl4 interface. The bound ligand, once approached by NBD2 during transient channel opening, lays at a multiple interdomain cross point. Thereafter, curcumin can bridge NBD1 and NBD2, and also ICL1/ICL4 and ICL2/ICL3 finally tightening the same interdomain interactions that normally uphold the active conformation in the wild type ATP-bound CFTR. The proposed binding site is compatible with biochemical observations made in previous CFTR-curcumin interaction studies. These findings provide the framework for the design of novel drugs that activate CFTR mutants characterized by defects in ATP binding and/or NBD dimerization, or even lacking NBD2.
ARTICLE | doi:10.20944/preprints201912.0083.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: hydrogenases; hydrogen fuel cells; homology modeling; fes clusters; transmembrane helices; molecular docking; molecular tunnels
Online: 6 December 2019 (11:47:06 CET)
Three-dimensional structure of six closely related hydrogenases from purple bacteria has been modeled by combining template-based and ab initio modeling approach. The results lead to conclusion that there should be 4Fe3S-cluster in the structure of these enzymes. Thus, these hydrogenases could drive attention for exploring their oxygen tolerance and practical applicability in hydrogen fuel cells. Analysis of 4Fe3S-cluster's microenvironment showed intragroup heterogeneity. Possible function of the C-terminal part of the small subunit in membrane binding has been discussed. Comparison of the built models with existing hydrogenases of the same subgroup (membrane-bound oxygen-tolerant hydrogenases) has been carried out. Analysis of intramolecular interactions in the large subunits showed statistically reliable differences in number of hydrophobic interactions and number of ionic interactions. Molecular tunnels were mapped in the models and compared with structures from PDB. Protein-protein docking showed that these enzymes could exchange electrons in oligomeric state, which is important for oxygen-tolerant hydrogenases. Molecular docking with model electrode compounds showed mostly the same results as with hydrogenases from E.coli, H. marinus, R. eutropha, S. enterica; some interesting results were shown in case of HupSL from Rba. sphaeroides and Rvx. gelatinosus.
REVIEW | doi:10.20944/preprints201705.0212.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: cancer; cell-surface receptor; EGFR; molecular mechanism; phosphorylation; receptor tyrosine kinase; transmembrane signal transduction
Online: 30 May 2017 (08:34:04 CEST)
The epidermal growth factor receptor (EGFR) plays vital roles in cellular processes including cell proliferation, survival, motility and differentiation. Dysregulated activation of the receptor is often implicated in human cancers. EGFR is synthesized as a single-pass transmembrane protein, which consists of an extracellular ligand-binding domain and an intracellular kinase domain separated by a single transmembrane domain. The receptor is activated by a variety of polypeptide ligands such as epidermal growth factor and transforming growth factor α. It has long been thought that EGFR is activated by ligand-induced dimerization of the receptor monomer, which brings intracellular kinase domains into close proximity for trans-autophosphorylation. An increasing number of diverse studies, however, demonstrate that EGFR is present as a pre-formed, yet inactive, dimer prior to ligand binding. Furthermore, recent progress in structural studies has provided insight into conformational changes during the activation of a pre-formed EGFR dimer. Upon ligand binding to the extracellular domain of EGFR, its transmembrane domains rotate or twist parallel to the plane of the cell membrane, resulting in reorientation of the intracellular kinase domain dimer from a symmetric inactive configuration to an asymmetric active form (the “rotation model”). This model is also able to explain how oncogenic mutations activate the receptor in the absence of ligand without assuming that the mutations induce receptor dimerization. In this review, we discuss mechanisms underlying ligand-induced activation of the preformed EGFR dimer, as well as how oncogenic mutations constitutively activate the receptor dimer, based on the rotation model.
ARTICLE | doi:10.20944/preprints202307.1616.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: cystic fibrosis; cystic fibrosis transmembrane conductance regulator gene; CFTR; next generation sequencing; cystic fibrosis carriers
Online: 25 July 2023 (05:35:21 CEST)
Keywords: Cystic fibrosis, Cystic Fibrosis Transmembrane Conductance Regulator gene, CFTR, Next Generation Sequencing, Cystic fibrosis carriers
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: magic-angle spinning; solid-state NMR; membrane protein; beta barrel; transmembrane; proton detection; high magnetic field
Online: 29 March 2021 (12:49:07 CEST)
The available magnetic field strength for high resolution NMR in persistent superconducting magnets has recently improved from 23.5 to 28 Tesla, increasing the proton resonance frequency from 1 to 1.2 GHz. For magic-angle spinning (MAS) NMR, this is expected to improve resolution, provided the sample preparation results in homogeneous broadening. We compare two-dimensional (2D) proton detected MAS NMR spectra of four membrane proteins at 950 and 1.2 GHz. We find a consistent improvement in resolution that scales superlinearly with the increase in magnetic field for three of the four examples. In 3D and 4D spectra, which are now routinely acquired, this improvement indicates the ability to resolve at least 2 and 2.5 times as many signals, respectively.
REVIEW | doi:10.20944/preprints202207.0464.v1
Subject: Medicine And Pharmacology, Urology And Nephrology Keywords: prostate cancer; six-transmembrane epithelial antigen of the prostate; biomarker; immunotherapy; cancer vaccine; T-cell engaging antibody
Online: 29 July 2022 (14:02:03 CEST)
Six-Transmembrane Epithelial Antigen of the Prostate 1-4 (STEAP1-4) compose a family of metalloproteinases involved in iron and copper homeostasis and other cellular processes. Thus far, five homologs are known: STEAP1, STEAP1B, STEAP2, STEAP3, and STEAP4. In prostate cancer, STEAP1, STEAP2, and STEAP4 are overexpressed while STEAP3 expression is downregulated. Although the metalloreductase activities of STEAP1-4 are well-documented, their other biological functions are not. Furthermore, the properties and expression levels of STEAP heterotrimers, homotrimers, heterodimers, and homodimers are not well-understood. Nevertheless, studies over the last few decades have provided sufficient impetus to investigate STEAP1-4 as potential biomarkers and therapeutic targets for prostate cancer. In particular, STEAP1 is the target of many emerging immunotherapies. Herein, we give an overview of the structure, physiology, and pathophysiology of STEAP1-4 to provide context for past and current efforts to translate STEAP1-4 into the clinic.
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: SARS-CoV-2; COVID-19; acute kidney injury; angiotensin converting enzyme II (ACE2); transmembrane serine protease (TMPRSSs)
Online: 23 February 2020 (15:42:24 CET)
Purpose: Acute kidney injury (AKI) is a severe symptom of the 2019 novel coronavirus disease (COVID-19), especially for patients in a critical condition.This study explored the potential mechanism of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on AKI at the single-cell level. Methods: 15 normal human kidney samples were collected and analyzed using single-cell RNA sequencing (scRNA-seq). Subsequently, we analyzed the components and proportions of kidney cells expressing the host cellular receptor ACE2 and the key protease TMPRSSs family, and analyzed the expression differences in Occidental and Asian populations. Results: We drafted the currently available world's largest human kidney cell atlas with 42,589 cells and identified 19 clusters through unsupervised hierarchical clustering analysis. ACE2 and TMPRSSs genes were significantly co-expressed in podocytes and proximal convoluted tubules as potential host cells targeted by SARS-CoV-2. Comparative analysis showed that ACE2 expression in kidney cells was no less than that in the lung, esophagus, small intestine and colon, suggesting that the kidney may be an important target organ for SARS-CoV-2. In addition, given the high expression of ACE2 and kidney disease-related genes in Occidental donors relative to Asian donors, Occidental populations with SARS-CoV-2 infection might be a higher risk of of kidney injury.
REVIEW | doi:10.20944/preprints202105.0414.v1
Subject: Medicine And Pharmacology, Epidemiology And Infectious Diseases Keywords: : mineralocorticosteroid receptor antagonist (MRA); angiotensin converting enzyme 2 (ACE2); SARS-CoV-2; transmembrane protease receptor serine 2; furin; plasmin
Online: 18 May 2021 (10:39:03 CEST)
Aims: Spironolactone is a steroidal mineralocoricosteroid receptor antagonist (MRA) used for treatment of resistant hypertension, heart failure and edema. It exerts class specific adverse effects that are shared by other MRAs. Additionally, it exerts unique “off target” steroidal effects that include gynecomastia, impotence and loss of libido in males and menstrual irregularity in females. Together, these have led to a poor tolerability and limited use despite positive results in many randomized, controlled clinical trials. We review the off-target effects of spironolactone that may summate with its MRA action to provide an advantageous profile for prevention or treatment of patients with COVID-19. Methods: Literature review using PubMed Central. Results: The blockade by spironolactone of the androgen receptor should diminish the expression of transmembrane protease serine 2 (TMPRSS2) that has an androgen promoter while its MRA action should enhance the expression of protease nexin1 (PN1) that inhibits furin and plasmin. TMPRSS2, furin and plasmin cooperated to process the SARS-CoV-2 spike protein to increase its high affinity binding to the angiotensin converting enzyme 2 (ACE2) and thereby promote viral cell entry. Its actions as an MRA may reduce inflammation and preserve pulmonary, cardiac and vascular functions. Its anti-plasmin action may combat hemostatic dysfunction. Conclusion: The hypothesis that the off-target effects of spironolactone summate with its MRA actions to provide special benefits for COVID-19 is worthy of direct investigation and clinical trial.
REVIEW | doi:10.20944/preprints202305.1708.v1
Subject: Biology And Life Sciences, Life Sciences Keywords: Cytoplasmic membrane homeostasis; Pathogenicity; Pathogenic fungi; Membrane lipid metabolism; Membrane curvature; Transmembrane protein; Cell wall components; Cytoskeleton; Growth and development; Host infection
Online: 24 May 2023 (10:38:22 CEST)
The cytoplasmic membrane is the fundamental component of all living cells, which participates in various physiological processes, such as material exchange, stress response, cell recognition, signal transduction, cellular immunity, apoptosis, pathogenicity, etc. The normal function of a cytoplasmic membrane requires stable organization of transmembrane protein-lipid microdomains, transmembrane protein-cell wall microdomains, and cytoskeleton-transmembrane protein microdomains. Here, we review the mechanisms and functions of various membrane lipid components, fatty acid content and saturation, membrane curvature, and cell wall and cytoskeleton in plasma membrane homeostasis affecting the pathogenicity of pathogenic fungi. Pathogenic fungi maintains plasma membrane homeostasis and contributes to fungal virulence by maintaining plasma membrane assembly, structural and functional integrity of pathogenic fungi at various stages of cell development through interactions among lipid components of cytoplasmic membranes, transmembrane proteins, cytoskeleton and cell wall components, etc.
ARTICLE | doi:10.20944/preprints202306.0366.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Liquid liquid phase separation; protein oligomerization; GO; domain-domain interaction; domain linker; intrinsically disordered regions; domain-peptide interaction; beta-sheet; transmembrane helices; post-translational modification
Online: 6 June 2023 (03:43:57 CEST)
Although there are a large number of databases available for regulatory elements, bottleneck has been created by the lack of bioinformatics tools for predicting types of mechanisms underlying actions of regulatory elements. To reduce the gap, we developed ARabidopsis Transcription regulatory Factor Domain-domain interaction Analysis Tool- Liquid-liquid phase separation (LLPS), Oligomerization, GO analysis (ART FounDATion-LOG), a useful toolkit for protein-nucleic acid interactions (PNI) and protein-protein interactions (PPI) analysis based on domain-domain interaction (DDI). LLPS, protein oligomerization, structural properties of protein domains, and protein modifications are major components in orchestrating spatio-temporal dynamics of PPI and PNI. Our goal is to integrate PPI/PNI information into development of prediction model for identifying important genetic variants in peach. The program unified inter-database relational keys by protein domains for facilitating inference from the model species. Key advantage of the program lies in the integrated information of related features: LOG, structural characterization of domain (e.g. domain linker, intrinsically disordered regions, DDI, domain-motif (peptide) interaction, beta-sheet and transmembrane helices), and post-translational modification. We provided simple tests to demonstrate how to use the program. The program may be applied to other eukaryotic organisms. The program codes and data are freely available for download at and https://sourceforge.net/projects/artfoundation-log/.
REVIEW | doi:10.20944/preprints202110.0016.v1
Subject: Medicine And Pharmacology, Oncology And Oncogenics Keywords: prostate cancer; castrate-resistant growth; metastases; androgen receptor; glucocorticoid receptor; cytokines; transmembrane receptors; cell signaling; pharmacological targeting; neuroendocrine differentiation; lineage plasticity; prostate cancer stem cells
Online: 1 October 2021 (12:19:03 CEST)
Understanding of the molecular mechanisms of prostate cancer has led to development of therapeutic strategies targeting androgen receptor (AR). These androgen-receptor signaling inhibitors (ARSI) include androgen synthesis inhibitor- abiraterone and androgen receptor antagonists- enzalutamide, apalutamide, and darolutamide. Although these medications provide significant improvement in survival among men with prostate cancer, drug resistance develops in nearly all patients with time. This could be through androgen-dependent or androgen-independent mechanisms. Even weaker signals and non-canonical steroid ligands can activate AR in the presence of truncated AR-splice variants, AR overexpression, or activating mutations in AR. AR splice variant, AR-V7 is the most studied among these and is not targeted by available ARSIs. Non-androgen receptor dependent resistance mechanisms are mediated by activation of an alternative signaling pathway when AR is inhibited. DNA repair pathway, PI3K/AKT/mTOR pathway, BRAF-MAPK and Wnt signaling pathway and activation by glucocorticoid receptors can restore downstream signaling in prostate cancer by alternative proteins. Multiple clinical trials are underway exploring therapeutic strategies to overcome these resistance mechanisms.