REVIEW | doi:10.20944/preprints202012.0553.v1
Online: 22 December 2020 (10:46:28 CET)
Solid tumors are typically associated with unbridled proliferation of malignant cells, accompanied by an immature and dysfunctional tumor-associated vascular network. Consequent impairment in transport of nutrients and oxygen eventually leads to a hypoxic environment wherein cells must adapt to survive and overcome these stresses. Hypoxia inducible factors (HIFs) are central transcription factors in the hypoxia response and drive the expression of a vast number of survival genes in cancer cells and in cells in the tumor microenvironment. HIFs are tightly controlled by a class of oxygen sensors, the HIF-prolyl hydroxylase domain proteins (PHDs), which hydroxylate HIFs, thereby marking them for proteasomal degradation. Remarkable and intense research during the past decade has revealed that, contrary to expectations, PHDs are often overexpressed in many tumor types and that inhibition of PHDs can lead to decreased tumor growth, impaired metastasis and diminished tumor-associated immune-tolerance. Therefore, PHDs represent an attractive therapeutic target in cancer research. Multiple PHD inhibitors have been developed that have either been recently accepted in China as erythropoiesis stimulating agents (ESA) or are currently in phase III trials. We review here the function of HIFs and PHDs in cancer and related therapeutic opportunities.
ARTICLE | doi:10.20944/preprints202110.0117.v1
Online: 7 October 2021 (11:00:12 CEST)
Leishmanial skin lesions are characterized by inflammatory hypoxia alongside the activation of hypoxia inducible factors, HIF-1a and HIF-2a, and subsequent expression of the HIF-a target VEGF-A during Leishmania major infection. However, the factors responsible for HIF-a activation are not known. We hypothesize hypoxia and pro-inflammatory stimuli contribute to HIF-a activation during infection. RNASeq on leishmanial lesions found transcripts associated with HIF-1a signaling are induced. To determine whether hypoxia contributes to HIF-a activation, we followed the fate of myeloid cells infiltrating from the blood and into hypoxic lesions. Recruited myeloid cells experience hypoxia when they enter inflamed lesions, and the length of time in lesions increases their hypoxic signature. To determine whether pro-inflammatory stimuli in the inflamed tissue can also influence HIF-a activation, we subjected macrophages to various pro-inflammatory stimuli and measured VEGF-A. While parasites alone did not induce VEGF-A, and pro-inflammatory stimuli only modestly induce VEGF-A, HIF- stabilization increases VEGF-A during infection. HIF-a stabilization does not impact parasite entry, growth or killing. Alternatively, the absence of ARNT/HIF- signaling enhances parasite internalization. Altogether, these findings suggest HIF-a is active during infection, and while macrophage HIF-a activation promotes lymphatic remodeling through VEGF-A production, HIF-a activation does not impact parasite internalization or control.
REVIEW | doi:10.20944/preprints202010.0136.v1
Online: 6 October 2020 (15:41:14 CEST)
Erythropoiesis is a complex process driving the production of red blood cells. During homeostasis, adult erythropoiesis takes place in the bone marrow and is tightly controlled by erythropoietin (EPO), a central hormone mainly produced in renal EPO-producing cells. The expression of EPO is strictly regulated by local changes in oxygen partial pressure (pO2) as under deprived oxygen (hypoxia) the transcription factor Hypoxia Inducible Factor-2 induces EPO. However, erythropoiesis regulation extends beyond the well-established HIF-EPO axis, and involves processes modulated by other hypoxia pathway proteins (HPPs), including proteins involved in iron metabolism. The importance of a number of these factors is evident as their altered expression has been associated with various anemia-related disorders, including chronic kidney disease. Eventually, our emerging understanding of HPPs and their regulatory feedback will be instrumental in developing specific therapies for anemic patients and beyond.
REVIEW | doi:10.20944/preprints202012.0112.v1
Subject: Life Sciences, Biochemistry Keywords: Hypoxia; HIF-1α; HIF-2α; Posttranslational modifications; Phosphorylation; Acetylation; Ubiquitination; Sumoylation; S-Nitrosylation; Signalling; cystein phosphorylation; methylation
Online: 4 December 2020 (13:45:45 CET)
The hypoxia signalling pathway enables adaptation of cells to decreased oxygen availability. When oxygen becomes limiting, the central transcription factors of the pathway, hypoxia-inducible factors (HIFs), are stabilised and activated to induce the expression of hypoxia-regulated genes, thereby maintaining cellular homeostasis. Whilst hydroxylation has been thoroughly described as the major and canonical modification of the HIF-α subunits, regulating both HIF stability and activity, a range of other post-translational modifications decorating the entire protein play also a crucial role in altering HIF localisation, stability, and activity. These modifications, their conservation throughout evolution and their effects on HIF-dependent signalling are discussed in this review.
REVIEW | doi:10.20944/preprints202002.0436.v1
Online: 28 February 2020 (13:07:04 CET)
It has been long recognized that under hypoxia conditions cancer cells reprogram their metabolism through shift from oxidative phosphorylation (OXPHOS) to glycolysis to meet elevated requirements in energy and nutrients for proliferation, migration and survival. However, data accumulated over the last years increasingly evidence that cancer cells can revert from glycolysis to OXPHOS and maintain both reprogrammed and oxidative metabolism even in the same tumor. The phenomenon denoted as cancer cell metabolic plasticity or hybrid metabolism depends on a tumor micro-environment, which is highly heterogeneous and influenced by intensity of vasculature and blood flow, oxygen concentration, nutrient and energy supply, and requires regulatory interplay between multiple oncogenes, transcription factors, growth factors, reactive oxygen species (ROS), etc. Hypoxia-inducible factor-1 (HIF-1) and AMP-activated protein kinase (AMPK) represent key modulators of switch between reprogrammed and oxidative metabolism. The present review focuses on cross-talks between HIF-1, GLUTs, and AMPK and other regulatory proteins including oncogenes such as c-Myc, p53 and KRAS, growth factor-initiated PKB/Akt, PI3K and mTOR signaling pathways and tumor suppressors such as LKB1 and TSC1 in controlling cancer cell metabolism. The multiple switches between metabolic pathways can underlie chemo-resistance to conventional anti-cancer therapy and should be taken into account in choosing molecular targets to discovery novel anti-cancer drugs.
ARTICLE | doi:10.20944/preprints202104.0359.v1
Online: 13 April 2021 (13:24:41 CEST)
PBRM1, a component of the chromatin remodeller SWI/SNF, is often deleted or mutated in human cancers, most prominently in renal cancers. Core components of the SWI/SNF complex have been shown to be important for the cellular response to hypoxia. Here we investigated how PBRM1 controls HIF-1alpha activity. We find that PBRM1 is required for HIF-1alpha transcriptional activity and protein levels. Mechanistically, PBRM1 is important for HIF-1alpha mRNA translation, as absence of PBRM1 results in reduced activly transalting HIF-1alpha mRNA. Interestingly, we find that PBRM1, but not BRG1, interacts with the m6A reader protein YTHDF2. HIF-1alpha mRNA is m6A modified, bound by PBRM1 and YTHDF2. PBRM1 is necessary for YTHDF2 binding to HIF-1alpha mRNA and reduction of YTHDF2 results in reduced HIF-1alpha protein expression in cells. Our results identify a SWI/SNF independent function for PBRM1, interacting with HIF-1alpha mRNA and the epitranscriptome machinery. Furthermore, our results suggests that the epitranscriptome associated proteins play a role in the control of hypoxia signalling pathways
ARTICLE | doi:10.20944/preprints202003.0168.v1
Subject: Life Sciences, Molecular Biology Keywords: NF-kappaB; HIF; ARNT; TRAF6; Transcription; ChIP; Drosophila
Online: 10 March 2020 (11:14:37 CET)
NF-B signalling is crucial for cellular responses to inflammation but has also been associated with the hypoxia response. NF-B and HIF transcription factors possess an intense molecular crosstalk. Although it is known that HIF-1beta modulates NF-kappaB transcriptional response, very little is understood regarding how HIF-1beta contributes to NF-kappaB signalling. Here, we demonstrate that HIF-1beta is required for full NF-kappaB activation in cells following canonical and non-canonical stimuli. We found that HIF-1beta specifically controls TRAF6 expression in human cells but also in Drosophila melanogaster. HIF-1beta binds to the TRAF6 gene and controls its expression independently of HIF-1alpha. Furthermore, exogenous TRAF6 expression is able to rescue all of the cellular phenotypes observed in the absence of HIF-1beta. These results indicate that HIF-1beta is an important regulator of NF-kappaB with consequences for homeostasis and human disease.
ARTICLE | doi:10.20944/preprints201703.0026.v1
Subject: Life Sciences, Molecular Biology Keywords: ovarian cancer; melatonin; angiogenesis; VEGF; VEGFR; HIF-1α
Online: 6 March 2017 (06:34:02 CET)
Angiogenesis is a hallmark of ovarian cancer (OC) it promotes rapid cell growth and the associated metastasis. Identifying new bioactive compounds to target angiogenesis may provide valuable paradigms as therapeutic strategies. Melatonin is a well-characterized indoleamine that possesses important anti-angiogenic properties in a set of aggressive solid tumors. Herein, we evaluated the role of melatonin therapy on the angiogenic signaling pathway in OC of an ethanol-preferring rat model that mimics the same pathophysiological conditions occurring in women. OC was chemically induced with a single injection of 7,12-dimethylbenz(a)anthracene (DMBA) under the ovarian bursa. After the rats developed serous papillary OC, half of the animals received i.p. injections of melatonin (200 µg/100 g body weight/day) for 60 days. Serum levels of melatonin were higher following therapy, and the expression of its receptor MT1R was significantly increased in OC-bearing rats, regardless of ethanol intake. TGFB1, a transforming growth factor-beta1, was reduced only after melatonin treatment. Importantly, vascular endothelial growth factor (VEGF) was severely reduced after melatonin therapy in animals given or not given ethanol. Conversely, the levels of VEGF receptor 1 (VEGFR1) was diminished after ethanol consumption, regardless of melatonin therapy, and VEGFR2 was only reduced following melatonin. Hypoxia-inducible factor (HIF)-1α was augmented with ethanol consumption, and notably, melatonin significantly reduced their levels. Collectively, our results suggest that melatonin attenuates angiogenesis in OC of an animal model of ethanol consumption; this provides a possible complementary therapeutic opportunity for concurrent OC chemotherapy.
ARTICLE | doi:10.20944/preprints201807.0007.v1
Subject: Life Sciences, Molecular Biology Keywords: HIF; NF-kappaB; EPAS1; LIGHT; TNFSF14; p52; NIK; ChIP
Online: 2 July 2018 (09:53:29 CEST)
Non-canonical NF-kB signalling plays important roles in development and function of the immune system but also is deregulated in a number of inflammatory diseases. Although, NF-kB and HIF crosstalk has been documented, this has only been described following canonical NF-kB stimulation, involving RelA/p50 and the HIF-1 dimer. Here we report that the non-canonical inducer TNFSF14/LIGHT leads to HIF induction and activation in cancer cells. We demonstrate that only HIF-2a is induced at the transcriptional level following non-canonical NF-kB activation, via a mechanism dependent on the p52 subunit. Furthermore, we demonstrate that p52 can bind to the HIF-2a gene in cells. These results indicate that non-canonical NF-kB can lead to HIF signalling implicating HIF-2a as one of the downstream effectors of this pathway in cells.
REVIEW | doi:10.20944/preprints202209.0354.v1
Subject: Medicine & Pharmacology, Other Keywords: Wound healing; metastasis; oxidative stress; macrophage; HIF; NF-kB; Nrf2
Online: 23 September 2022 (03:28:28 CEST)
Many signaling pathways, molecular and cellular actors which are critical for wound healing have been implicated in cancer metastasis. These two conditions are a complex succession of cellular biological events and accurate regulation of these events is essential. Apart from inflammation, macrophages-released ROS arise as major regulators of these processes. But, whatever the pathology concerned, oxidative stress is a complicated phenomenon to control and requires a finely tuned balance over the different stages and responding cells. This review provides an overview of the pivotal role of oxidative stress in both wound healing and metastasis, encompassing the contribution of macrophages. Indeed, macrophages are major ROS producers but also appear as their targets since ROS interfere with their differentiation and function. Elucidating ROS functions in wound healing and metastatic spread may allow the development of innovative therapeutic strategies involving redox modulators.
Subject: Medicine & Pharmacology, Allergology Keywords: Mitochondria; cytochrome c oxidase; COX4-1; COX4-2; HIF-1α
Online: 10 February 2021 (10:58:33 CET)
Cytochrome-c-oxidase (COX) subunit 4 (COX4) plays important roles in the function, assembly and regulation of COX (mitochondrial respiratory complex 4), the terminal electron acceptor of the oxidative phosphorylation (OXPHOS) system. The principal COX4 isoform, COX4-1, is expressed in all tissues, whereas COX4-2 is mainly expressed in the lungs, or under hypoxia and other stress conditions. We have previously described a patient with a COX4-1 defect with a relatively mild presentation compared to other primary COX deficiencies, and hypothesized that this could be the result of compensatory upregulation of COX4-2. To this end, COX4-1 was downregulated by shRNAs in human foreskin fibroblasts (HFF), and compared to patient's cells. COX4-1, COX4-2 and HIF-1α were detected by immunocytochemistry. The mRNA transcripts of both COX4 isoforms and HIF-1 target genes were carried out by RT-qPCR. COX activity and OXPHOS function were measured by enzymatic and oxygen consumption assays, respectively. Pathways were analyzed by CEL-Seq2 and by RT-qPCR. We demonstrate elevated COX4-2 levels in the COX4-1-deficient cells with a concomitant HIF-1α stabilization, nuclear localization and upregulated hypoxia and glycolysis pathways. We suggest that COX4-2 and HIF-1α has the are upregulated, also in normoxia as a compensatory mechanism in COX4-1 deficiency.
REVIEW | doi:10.20944/preprints201803.0004.v1
Subject: Life Sciences, Molecular Biology Keywords: hypoxia; chromatin; transcriptional repression; repressor complexes; JmjC; histone methylation; HIF
Online: 1 March 2018 (06:36:57 CET)
Hypoxia, or reduced oxygen availability, has been studied extensively for its ability to activate specific genes. Hypoxia induced gene expression is mediated by the HIF transcription factors, although not exclusively so. Despite the great knowledge on the mechanisms by which hypoxia activates genes, much less is known about how hypoxia promotes gene repression. In this review, we discuss the potential mechanisms underlying hypoxia-induced transcriptional repression responses. We highlight HIF-dependent and independent mechanisms, but also the potential roles of dioxygenases with functions at the nucleosome and DNA level. Finally, we discuss recent evidence regarding the involvement of transcriptional repressor complexes in hypoxia.
REVIEW | doi:10.20944/preprints202209.0457.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: Anti-angiogenic; HIF-1 α; Normalization-window; research; hypoxia; resistance; SBRT; Immunotherapy
Online: 29 September 2022 (08:06:17 CEST)
Multiple biological pathways manifest and latent, meant for human survival, become a liability in cancer cure. With an increasing understanding of innumerable complex paths, cancer progression and development of resistance is no surprise. For the three “vasculature-immune-phenotypic” fundamental changes, hypoxia is the maestro orchestrating the whole gamut of changes (through the master manipulator - HIF-1 α), simultaneously transactivating hundreds of pro-angiogenic genes. Such a complex molecular bio-network begs the question, “Is our cancer research caught in such a tangled web that we have lost sight of the Spider?”. Hypoxia is this Spider weaving compensatory webs with every intervention/ obstruction. Anti-angiogenic (AAG) research has been conducted mainly in silos – exploring independent paths. This review conceptualizes a convergence of a multitude of research worldwide to a single theme of normalizing vasculature as a primary baseline for overcoming resistance to AAGs or their combinations.
Subject: Biology, Anatomy & Morphology Keywords: Hypoxia Inducible Factor; HIF; Ischemia; Hypoxia; Adaptation; Alzheimer’s Disease; Parkinson Disease; Neurodegeneration
Online: 26 February 2021 (15:34:31 CET)
Hypoxia is one of the most common pathological conditions which results from ischemic injury, trauma, inflammatory conditions, tumors, The adaptation of the body to hypoxia is a phenomenon that is of great importance both in normal conditions and in Most of the cellular response’ reactions to hypoxia is associated with a family of transcription factors called hypoxia-inducible factors (HIF). They induce the expression of a wide range of genes that help cells adapt to a hypoxic HIF functions are currently being extensively studied. In 2019, William G. Kaelin and Gregg Semenza from the USA and Sir Peter J. Ratcliffe from the UK received the Nobel Prize in Physiology or Medicine for the discovery of the basic mechanisms of adaptation to hypoxia and investigation of the role of HIF factor in the regulation of the hormone erythropoietin Based on its pivotal physiological importance, the HIF factor attracts more and more attention as a new potential target for treating a large number of diseases associated with Most of the experimental work dealing with the HIF factor is focused on its role in liver and However, increasing amount of experimental results clearly demonstrates that the HIF factor-based response represents an universal adaptation mechanism for all kinds of tissues, including the nervous system where HIF is critical for regulating neurogenesis, nerve cell differentiation, and neuronal This review provides actual overview about the complex role of HIF-1 in the adaptation of nerve cells to hypoxia with the focus on its potential role by various neuronal
REVIEW | doi:10.20944/preprints202003.0285.v1
Subject: Medicine & Pharmacology, Oncology & Oncogenics Keywords: HIF-1α; NQO1; hypoxia; angiogenesis; cancer; protein:protein interactions; ligand binding; proteasomal degradation
Online: 18 March 2020 (08:45:33 CET)
HIF-1α is a master regulator of oxygen homeostasis involved in different stages of cancer development. Thus, HIF-1α inhibition represents an interesting target for anti-cancer therapy. It was recently shown that HIF-1α interaction with NQO1 inhibits its proteasomal degradation, thus suggesting that targeting the stability of NQO1 could led to destabilization of HIF-1α as a therapeutic approach. Since the molecular interactions of NQO1 with HIF-1α are beginning to be unraveled, we review here our current knowledge on the intracellular functions and stability of NQO1, its pharmacological modulation by small ligands, and the molecular determinants of its roles as a chaperone of many different proteins including cancer-associated factors such as p53 and p73α. This knowledge is then discussed in the context of potentially targeting the intracellular stability of HIF-1α by acting on its chaperone, NQO1. This could result in novel anti-cancer therapies.
REVIEW | doi:10.20944/preprints202005.0284.v1
Subject: Life Sciences, Other Keywords: hypoxia; HIF-1α; partial EMT; collective migration; inflammatory breast cancer; E-cadherin; metastasis
Online: 17 May 2020 (08:19:42 CEST)
Epithelial-mesenchymal transition (EMT) is a cellular biological process involved in migration of primary cancer cells to secondary sites facilitating metastasis. Besides, EMT also confers properties such as stemness, drug resistance and immune evasion which can aid a successful colonization at the distant site. EMT is not a binary process; recent evidence suggests that cells in partial EMT or hybrid E/M phenotype(s) can have enhanced stemness and drug resistance as compared to those undergoing a complete EMT. Moreover, partial EMT enables collective migration of cells as clusters of circulating tumor cells or emboli, further endorsing that cells in hybrid E/M phenotypes may be the ‘fittest’ for metastasis. Here, we review mechanisms and implications of hybrid E/M phenotypes, including their reported association with hypoxia. Hypoxia-driven activation of HIF-1α can drive EMT. In addition, cyclic hypoxia, as compared to acute or chronic hypoxia, shows the highest levels of active HIF-1α and can augment cancer aggressiveness to a greater extent, including enriching for a partial EMT phenotype. We also discuss how metastasis is influenced by hypoxia, partial EMT and collective cell migration, and call for a better understanding of interconnections among these mechanisms. We discuss the known regulators of hypoxia, hybrid EMT and collective cell migration and highlight the gaps which needs to be filled for connecting these three axes which will increase our understanding of dynamics of metastasis and help control it more effectively.
ARTICLE | doi:10.20944/preprints201810.0105.v1
Subject: Medicine & Pharmacology, Cardiology Keywords: 1; brain protection 2; HTK 3; cardiac arrest 4; hypoxic injury 5; HIF-1α
Online: 5 October 2018 (15:45:43 CEST)
Ischemic neuron loss contributes to brain dysfunction in patients with cardiac arrest (CA). Histidine–tryptophan–ketoglutarate (HTK) solution is a preservative used during organ transplantation. Can HTK also protect neurons from severe hypoxia (SH) following CA? We isolated rat primary cortical neurons and induced SH with or without HTK. Changes in caspase-3, hypoxia-inducible factor 1-alpha (HIF-1α), and NADPH oxidase-4 (NOX4) expression were evaluated at different time points till 72 h. Using a rat asphyxia model, we induced CA-mediated brain damage and then completed resuscitation. HTK or sterile saline was administered into the left carotid artery. Neurological deficit scoring and mortality were evaluated for 3 days. Then the rats were sacrificed for evaluating NOX4 and H2O2 level in blood and brain. In the in vitro study, HTK attenuated SH- and H2O2-mediated cytotoxicity in a volume- and time-dependent manner, associated with persisted HIF-1α expression, reductions in procaspase-3 activation and NOX4 expression. The inhibition of HIF-1α abrogated HTK’s effect on NOX4. In the in vivo study, neurological scores were significantly improved by HTK. H2O2 level, NOX4 activity and NOX4 gene expression were all decreased in the brain specimen of HTK-treated rats. Our results suggest that HTK acts as an effective neuroprotective solution.
ARTICLE | doi:10.20944/preprints201810.0687.v1
Subject: Engineering, Electrical & Electronic Engineering Keywords: Discrete Wavelet Transform (DWT); Adaptive Neuro-Fuzzy Inference System (ANFIS); Fuzzy Logic system (FLS); High Impedance Fault (HIF).
Online: 29 October 2018 (13:44:25 CET)
This paper presents a method to detect and classify the high impedance fault that occur in the medium voltage distribution network using discrete wavelet transform (DWT) and adaptive neuro-fuzzy inference system (ANFIS). The network is designed using Matlab software and various faults such as high impedance, symmetrical and unsymmetrical fault have been applied to study the effectiveness of the proposed ANFIS classifier method. This is achieved by training the ANFIS classifier using the features (standard deviation values) extracted from the three phase fault current signal by DWT technique for various cases of fault with different values of fault resistance in the system. The success and discrimination rate obtained for identifying and classifying the high impedance fault from the proffered method is 100% whereas the values are 66.7% and 85% respectively for conventional fuzzy based approach. The results indicate that the proposed method is more efficient to identify and discriminate the high impedance fault accurately from other power system faults in the system.
REVIEW | doi:10.20944/preprints202207.0171.v1
Subject: Medicine & Pharmacology, Behavioral Neuroscience Keywords: Alzheimer’s; aging; amygdala; brain plasticity; CA1; CA3; chronic stress; cognition; GABA; HIF-1; hippocampus; hypoxia; neurogenesis; Parkinson’s; prefrontal cortex; PSA-NCAM; ROS; spatial learning
Online: 12 July 2022 (04:25:55 CEST)
Stress plays a central role in functioning for all life forms. As humans, we experience stress in a multitude of ways through various types of stimuli. Due to the constancy of stressors in our lives, the nervous system has learned to allosterically adapt to the stimuli, but when the body cannot adapt, chronic stress can have morphological and degenerative impacts on neuroanatomy and cognitive function that may or may not be reversible. This literature review aimed to identify the specific neuroanatomical structures impacted most by the long-term effects of chronic stress and the subsequent relationship the morphological changes had on cognitive function in rodent models. We examined articles published from PubMed, Google Scholar, and Science Direct, while focusing the search on anatomical and neurodegenerative effects associated with chronic stress stimuli. The degenerative effects of various types simulated physiological chronic stress showed the most impact on neurogenesis and neuronal development, brain plasticity, and spatial learning and memory with association to the hippocampus. The hippocampus, amygdala, prefrontal cortex, and hypothalamic-pituitary-adrenal axis (HPA) all had reversible and non-reversible morphological alterations, which also had a direct impact on the brain’s cognitive abilities. While studies regarding chronic stress are still being conducted, future research may be able to further highlight why stressful stimuli can particularly impact these structures and the tangential impacts that it may have on related or adjacent structures.
REVIEW | doi:10.20944/preprints202010.0510.v1
Subject: Life Sciences, Biochemistry Keywords: disease-associated mutation; IDR; intrinsically disordered region; LLPS; phase separation; PTM; Ahr; AhRR; SIM1; SIM2; Hif-2α; NPAS4; ARNT2; BMAL1; disorder prediction; LLPS prediction; cancer; HuVarBase; catGranule prediction
Online: 26 October 2020 (10:30:47 CET)
The bHLH-PAS proteins are a family of transcription factors regulating expression of a wide range of genes involved in different functions, from differentiation and development control, by oxygen and toxins sensing to circadian clock setting. In addition to the well-preserved DNA-binding bHLH and PAS domains, bHLH-PAS proteins contain long intrinsically disordered C-terminal regions, responsible for their activity regulation. Our aim was to analyse the potential connection between disordered regions of the bHLH-PAS transcription factors with posttranscriptional modifications and liquid-liquid phase separation in the context of the disease-associated missense mutations. Highly flexible disordered regions, enriched in short more ordered motives, are responsible for wide spectrum of interactions with transcriptional co-regulators. Based on our in silico analysis and taking into account fact that transcription factors functions can be modulated by posttranslational modifications and spontaneous phase separation, we assume that the location of missense mutations inducing disease states, is clearly related to sequences directly undergoing these processes or to sequences responsible for their activity regulation.