The “tubulin code” combines different α/β-tubulin isotypes with several post-translational modifications (PTMs) to generate microtubule diversity in cells. During cell division, specific microtubule populations in the mitotic spindle are differentially modified, but only recently has the functional significance of these modifications started to be elucidated. In particular, α-tubulin detyrosination of stable microtubules in the spindle was shown to guide chromosomes during congression to the metaphase plate and allow the discrimination of mitotic errors, whose correction is required to prevent chromosomal instability (CIN), a hallmark of human cancers. Although alterations in certain tubulin PTMs have been reported in human cancers, it remains unclear whether and how tubulin PTMs have any functional implications for cancer cell properties. Here we review the role of the tubulin code in chromosome segregation during mitosis, together with the emerging cancer tubulin code and discuss possible links, as well as the respective diagnostic, prognostic and therapeutic implications for human cancers.

The success of Toxoplasma gondii (intracellular parasite) host cell invasion relies on the apical complex, a specialized microtubule cytoskeleton structure associated with secretory organelles. The genome encodes three isoforms of both α- and β-tubulin which are altered by specific post-translational modifications (PTMs), changing the biochemical/biophysical proprieties of microtubules, and modulating their interaction with associated proteins. Tubulin PTMs are a powerful and evolutionarily conserved mechanism to generate tubulin diversity, forming a biochemical ‘tubulin code’ that can be ‘read’ by microtubule-interacting factors. The T. gondii tubulin PTMs are: α-tubulin acetylation, α-tubulin detyrosination, Δ5α-tubulin, Δ2α-tubulin, α- and β-tubulin polyglutamylation, and α- and α-tubulin methylation. Tubulin glutamylation is a key candidate to assist microtubule remodeling in Toxoplasma, being involved in the regulation of microtubule stability, dynamics, interaction with motor proteins, and severing enzymes. The correct balance of tubulin glutamylation is achieved by the coordinated action of polyglutamylases and deglutamylating enzymes. In this work we will review and discuss the current knowledge on T. gondii tubulin glutamylation. By in silico identification of mammalian protein orthologs we explored and updated the identification of putative proteins related to glutamylation, contributing to a better understanding of the role of tubulin glutamylation in T. gondii.

Tubulin superfamily (TSF) proteins are widespread and known for multifaceted roles as cytoskeletal proteins underpinning many basic cellular functions including morphogenesis, division, and motility. In eukaryotes, tubulin assembles into microtubules, a major component of the dynamic cytoskeletal network of fibres, whereas the bacterial homolog FtsZ assembles the division ring at midcell. Functions of the lesser-known archaeal TSF proteins are beginning to be identified, and show surprising diversity, including homologs of tubulin and FtsZ, and a third archaea-specific family, CetZ, implicated in the regulation of cell shape and possibly other unknown functions. In this study, we defined sequence and structural characteristics of the CetZ family and CetZ1 and CetZ2 subfamilies, identified CetZ groups and diversity amongst archaea, and identified potential functional relationships through analysis of the genomic neighbourhoods of cetZ genes. At least three subfamilies of orthologous CetZ proteins were identified in the archaeal class Halobacteria, including CetZ1 and CetZ2 and a novel uncharacterized subfamily. CetZ1 and CetZ2 were correlated to one another and to cell shape and motility phenotypes across diverse Halobacteria. Amongst other known CetZ clusters in orders Archaeoglobales, Methanomicrobiales, Methanosarcinales, and Thermococcales, an additional uncharacterized group from Archaeoglobales and Methanomicrobiales affiliated strongly with Halobacteria CetZs, suggesting they originated via horizontal transfer. Subgroups of Halobacteria CetZ2 and Thermococcales CetZ genes were found adjacent to different type IV pili regulons, suggesting a potential utilization of CetZs by type IV systems. More broadly conserved cetZ gene neighbourhoods included nucleotide and cofactor biosynthesis (e.g., F420) and predicted cell surface sugar epimerase genes. The findings imply that CetZ subfamilies are involved in multiple functions linked to the cell surface, biosynthesis and motility.

In celIs, microtubule location, length, and dynamics are regulated by a host of microtubule-associated proteins and enzymes that read where to bind and act based on the microtubule “tubulin code,” which is predominantly encoded in the tubulin carboxy-terminal tail (CTT). Katanin is a highly conserved AAA ATPase enzyme that binds to the tubulin CTTs to remove dimers and sever microtubules. We have previously demonstrated that short CTT peptides are able to inhibit katanin severing. Here, we examine effects of CTT sequences on this inhibition activity. Specifically, we examine CTT sequences found in nature, alpha1A (TUBA1A), detyrosinated alpha1A, Δ2 alpha1A, beta5 (TUBB/TUBB5), beta2a (TUBB2A), beta3 (TUBB3), and beta4b (TUBB4b). We find that these natural CTTs have distinct abilities to inhibit, most noticeably beta3 cannot inhibit katanin. Two non-native CTT tail constructs are also unable to inhibit – despite having 94% sequence identity with alpha1 or beta5 sequences. Surprisingly, we demonstrate that poly-E and poly-D peptides are capable of inhibiting katanin significantly. An analysis of the hydrophobicity of the CTT constructs indicates that more hydrophobic polypeptides are less inhibitory than more polar polypeptides. These experiments not only demonstrate inhibition, but also likely interaction and targeting of katanin to these various CTTs when they are part of a polymerized microtubule filament.

Tubulin and heat shock protein 27 (HSP27) are up-regulated in cancer cells, and play a critical role in cell division, and proliferation. Therefore, they are targets for discovery of anticancer therapy. The objective of this study is to design, characterize, and biologically evaluate the nimesulide analogues to combat female cancer such as ovarian cancer, and breast cancer. Herein, the nimesulide analogues are designed to target both tubulin and HSP27 functions. Ovarian cancer (SKOV3) and breast cancer (SKBR3) cell lines were used as surrogate models to test the nimesulide analogs biological activities using MTT assay. In the present study, four nimesulide analogues were designed, synthesized and the chemical structures were with the biological evaluation were studied. The synthesized agents were characterized by 1H-NMR, 13C-NMR, the molecular weight was confirmed using GC-MS technique, and melting point. Besides, the agent L4 structure was confirmed using X-ray crystallographic analysis. The present data revealed that nimesulide analogs have potent anticancer activity against SKOV3and SKBR3 cell lines. The IC50 values for both SKOV3 and SKBR3 cell lines treated with the agents showed a potent cell growth inhibition range of 0.23-2.02 µM and 0.50-3.73 µM respectively. In conclusion, the designed nimesulide analogues can target both tubulins, and HSP27 concurrently, and they are promising agents as future chemotherapy female cancers.

This study describes the design and development of novel compounds aimed at optimizing the function of microtubules and tubulin in the immune system and the brain as they relate to the Orch OR theory of consciousness. These compounds are defined by the following molecular formulas:C65H100CoN15O22P(C6H12O5);C65H100CoN15O22P(C5H10NO4);(C65H100CoN15O22P)(C6H12N2O)n;(C65H100CoN15O22P)(C6H12O5)(C6H12N2O)n;(C6H12N2O)n(C6H12O5)m;Zn(C6H12O5)2;These molecules, formulated under the form of drugs, health functional foods, or food supplements, have the potential to positively affect a number of areas ranging from prevention and therapy of neurological diseases to supporting the immune system.

In this article, we consider the relationship between the brain and the immune system in the context of the Orch OR (Orchestrated Objective Reduction) theory of consciousness. Orch OR is a theory that postulates that consciousness arises from quantum computations occurring inside microtubules. The immune system is capable of acquiring, learning, and remembering information, thus showing all the attributes of natural intelligence. We argue that the immune system also has the attribute of consciousness and can gain access to an amount of information greater than what is accessible to the brain since it is not constrained by brain's reducing valve that is responsible for cognitive bottlenecks. We also describe the role of meditation and religious chanting in affecting the brain and immune system. We speculate that some effects of religious chanting on the immune system may not be mediated by the brain. Finally, we examine the role of the immune system in connecting with the consciousness embedded in the universe.

Recent evidence obtained in murine atrial cardiomyocytes suggests that the behavior of tubulin, a constituent of microtubules, is influenced by audible sounds. In the present study, the sequence and the structure of murine and human tubulins were compared with those of human TMC1 (Transmembrane channel-like protein 1), a sound-sensitive protein that is responsible for forming the pore of mechanosensory transduction channels in the hair cells of the inner ear of vertebrates, and with those of bacterial FtsZ (Filamenting temperature-sensitive mutant Z), a bacterial protein homologous to tubulin. The results show that mouse and human alpha-tubulin are 100% identical, whereas sequence homology of human TMC1 and human tubulin alpha 1A chain is scarce, with only 17.31% identity. A higher degree of similarity was observed in the presence of aromatic amino acids as well as in the propensity to form alpha-helices. Based on these results, it is hypothesized that the response of tubulin to audible sounds is mediated by the external alpha-helices as it occurs in TMC1. The sequence homology of human TMC1 and FtsZ from Lactobacillus johnsonii, is moderate with 23.40% identity, however higher than that between TMC1 and tubulin. The overall presence of aromatic amino acids in FtsZ is scarce, but helix propensity is significant. These results are discussed in the context of Orch OR, a theory that postulates that consciousness emerges from quantum computations occurring in microtubules of neurons via information processing mediated by aromatic amino acids of tubulin.

Among bryophytes, the Plagiochila genus represents a large group of leafy liverworts, with over 500 species. Plagiochilins A-to-X are sesquiterpenoids isolated from Plagiochila species. The lead compound plagiochilin A (Plg-A), endowed with anticancer and anti-parasitic properties, has been characterized as a potent mitosis inhibitor, acting selectively at the late stage of cytokinesis termed abscission. The compound perturbs the dynamic of microtubules, blocking cell cycle progression and triggering the death of malignant cells. Based on the compound mechanism of action and the analogy with other natural products bearing a dihydro-pyrone moiety, we postulated that Plg-A could bind to the pironetin site of α-tubulin. A molecular docking analysis has been performed to compare binding of all 24 plagiochilins to α-tubulin and to establish structure-binding relationships. The identification of Plg-E and Plg-G as the best binders in the series pointed out to the importance of the C13-OH or C=O group for α-tubulin recognition. This observation led to the testing of the natural product ester plagiochilin A-15-yl n-octanoate and the corresponding alcohol (Plg-OH), both identified as robust α-tubulin binders. The study provides a rational to explain potentially the mechanism of action of Plg-A and to guide the design of new derivatives.

Structurally related 7-acetyl-2-aryl-5-bromoindoles 2a–d and the 7-acetamido-2-aryl-5-bromoindoles 4a–d as well as their corresponding 3-trifluoroacetyl–substituted derivatives 5a–d and 5e–h were evaluated for potential antigrowth effect in vitro against the human lung cancer (A549) and cervical cancer (HeLa) cells. All of the 3-trifluoroacetyl–substituted 7-acetamido-2-aryl-5-bromoindoles 5e–h were found to be more active against both cell lines when compared to the chemotherapeutic drug, Melphalan. The most active compound 5g induced apoptosis in a caspase dependent manner for both cell lines. Compounds 5e–h were found to significantly inhibit tubulin polymerization. Molecular docking of 5g into the colchicine-binding site suggests that the compounds bind to tubulin by different type of interactions including pi-alkyl, amide-pi stacked and alkyl interactions as well as hydrogen bonding with the protein residues to elicit anticancer activity.

(1) Background: In this work, a series of benzimidazole derivatives containing colchicine-like and cathechol-like moieties with methyl group substitution in the benzimidazole ring were evaluated for their in vitro antiproliferative, pro-apoptotic and antioxidative activity against highly invasive breast cancer cell line MDA-MB-231 and related impairment of tubulin dynamics; (2) Methods: MTT assay was used to evaluate the antiproliferative activity. In vitro tubulin polymerization assay as well as docking analysis was applied to prove the alterations in tubulin polymerization. Immunofluorescent and DAPI staining reveal the pro-apoptotic potential of benzimidazole derivatives and the effect on tubulin’s dynamics in living cells. The antioxidant activity was evaluated by scavenging of H2O2 and hypochlorite ion and ortho-phenanthroline tests; (3) Results: The compounds containing colchicine-like moiety displayed significant growth inhibitory effect against cancer cell line as was highlighted the role of methyl functional group on the tubulin aggregation and blockage of mitosis. All compounds showed an ability to scavenge H2O2, while the compounds with cathecol-like moiety were more effective against hypochlorite ion and chelation of iron; (4) Conclusions: The benzimidazole derivative containing colchicine-like moiety and methyl group substitution in benzimidazole ring is a potential antiproliferative and microtubule destabilizing agent.

Nowadays, an increasing number of heterocyclic-based drugs found application in medicinal chemistry and, in particular, as anticancer agents. In this context, oxadiazoles, five-membered aromatic rings, emerged for their interesting biological properties. Modification of oxadiazole scaffolds represents a valid strategy to increase their anticancer activity, especially on 1,2,4 and 1,3,4 regioisomers. In the last years, an increasing number of oxadiazole derivatives, with remarkable cytotoxicity for several tumor lines, were identified. Structural modifications, that ensure higher cytotoxicity towards malignant cells, represent a solid starting point in the development of novel oxadiazoles-based drugs. To increase the specificity of this strategy, outstanding oxadiazole scaffolds have been designed to selectively interact with biological targets, including enzymes, globular proteins and nucleic acids, showing more promising antitumor effects. In the present work, we aim to provide a comprehensive overview of the anticancer activity of these heterocycles, describing their effect on different targets and highlighting how their structural versatility has been exploited to modulate their biological properties.

Arf-like protein 2 (ARL2) is a ubiquitously expressed small GTPase with multiple functions. In cell culture, ARL2 participates with tubulin cofactor D (TBCD) in the neogenesis of tubulin αβ-heterodimers, the building blocks of microtubules. To evaluate this function in retina, we conditionally deleted ARL2 in mouse retina at two distinct stages, either during embryonic development (retArl2-/-) or after ciliogenesis specifically in rods (rodArl2-/-). retArl2-/- retina sections displayed distorted nuclear layers and a disrupted microtubule cytoskeleton (MTC) as early as postnatal day 6 (P6). Rod and cone outer segments (OS) did not form. By contrast, rod ARL2 knockouts were stable at postnatal day 35 and revealed normal ERG responses. Cytoplasmic dynein is reduced in retArl2-/- inner segments (IS), suggesting that dynein may be unstable in the absence of a normal MTC. We investigated microtubular stability in the absence of either ARL2 (retARL2-/-) or DYNC1H1 (retDync1h1-/-), the dynein heavy chain, and found that both the retArl2-/- and retDync1h1-/- retinas exhibited reduced microtubules and nuclear layer distortion. The results suggest that ARL2 and dynein depend on each other to generate a functional MTC during early photoreceptor development.

Human Perrault syndrome (PRLTS) is defined by autosomal recessive inheritance with primary ovarian insufficiency and early hearing loss. Most PRLTS disease proteins modulate mitochondrial transcription or translation. Among the genetic causes are ClpP mutations, which trigger also complete azoospermia, whose cellular and molecular underpinnings are unknown. Here, the ClpP-null mouse model was studied by global transcriptomics, proteomics, RT-qPCR, immunoblots, tissue fractionation, testis histology, and was crossed with STING/IFNAR mutants. Spermatogenesis showed accumulated early spermatocytes, versus deficits of desynapsis and kinetochore factors; excess Dazl/Stra8 and acetylSMC3, versus deficient SHCBP1L, were molecular correlates. Spermiogenesis showed few round spermatids, tsHMG/TFAM in elongated spermatids was absent; transcripts for tail/acrosome factors were downregulated from start. Nuclear anomalies included a failed Rec8 induction, early BRDT deficiency, histone H3 cleavage, and cGAMP increase, among antiviral responses typical of ClpP-mutants. However, deletion of downstream innate immune signals STING/IFNAR failed to reestablish fertility. As mitochondrial triggers, we observed accumulation of ClpX, with PTCD1, POLDIP2, GRSF1, ALKBH7, DNAJA3, AURKAIP1, VWA8, and Perrault proteins ERAL1, PEO1, HARS2, partially showing nuclear redistribution. ClpP-depletion is known to cause extra-mitochondrial release of mispacked mtDNA/mtRNA/protein complexes. Now we define nuclear inflammatory responses and meiotic arrest as consequences, similar to observations in mito-mice and mutator-mice.

Human Perrault syndrome (PRLTS) is defined by autosomal recessive inheritance with primary ovarian insufficiency and early hearing loss. Most PRLTS disease proteins modulate mitochondrial transcription or translation. Among the genetic causes are ClpP mutations, which trigger also complete azoospermia, whose cellular and molecular underpinnings are unknown. Here, the ClpP-null mouse model was studied by global transcriptomics, proteomics, RT-qPCR, immunoblots, tissue fractionation, testis histology, and was crossed with STING/IFNAR mutants. Spermatogenesis showed accumulated early spermatocytes, versus deficits of desynapsis and kinetochore factors; excess Dazl/Stra8 and acetylSMC3, versus deficient SHCBP1L, were molecular correlates. Spermiogenesis showed few round spermatids, tsHMG/TFAM in elongated spermatids was absent; transcripts for tail/acrosome factors were downregulated from start. Nuclear anomalies included a failed Rec8 induction, early BRDT deficiency, histone H3 cleavage, and cGAMP increase, among antiviral responses typical of ClpP-mutants. However, deletion of downstream innate immune signals STING/IFNAR failed to reestablish fertility. As mitochondrial triggers, we observed accumulation of ClpX, with PTCD1, POLDIP2, GRSF1, ALKBH7, DNAJA3, AURKAIP1, VWA8, and Perrault proteins ERAL1, PEO1, HARS2, partially showing nuclear redistribution. ClpP-depletion is known to cause extra-mitochondrial release of mispacked mtDNA/mtRNA/protein complexes. Now we define nuclear inflammatory responses and meiotic arrest as consequences, similar to observations in mito-mice and mutator-mice.

Zika virus (ZIKV) infection and pathogenesis are linked to the disruption of neurogenesis, congenital Zika syndrome and microcephaly by affecting neural progenitor cells. Nonstructural protein 5 (NS5) is the largest product encoded by ZIKV-RNA and is important for replication and immune evasion. Here, we studied the potential effects of NS5 on microtubules (MTs) and autophagy flux, together with the interplay of NS5 with histone deacetylase 6 (HDAC6). Fluorescence microscopy, biochemical cell-fractionation combined with the use of HDAC6 mutants, chemical inhibitors and RNA interference indicated that NS5 accumulates in nuclear structures and strongly promotes the acetylation of MTs that aberrantly reorganize in nested-like structures. Similarly, NS5 accumulates the p62 protein, an autophagic-flux marker. Therefore, NS5 alters events that are under the control of the autophagic tubulin-deacetylase HDAC6. HDAC6 appears to degrade NS5 by autophagy in a deacetylase- and BUZ domain-dependent manner and to control the cytoplasmic expression of NS5. Moreover, NS5 inhibits RNA-mediated RIG-I interferon (IFN) production, resulting in greater activity when autophagy is inhibited (i.e., effect correlated with NS5 stability). Therefore, it is conceivable that NS5 contributes to cell toxicity and pathogenesis, evading the IFN-immune response by overcoming HDAC6 functions. HDAC6 has emerged as an anti-ZIKV factor by targeting NS5.

Tumor vasculature proliferates rapidly, generally lacks pericyte coverage, and is uniquely frag-ile making it an attractive therapeutic target. A subset of small-molecule tubulin binding agents cause disaggregation of the endothelial cytoskeleton leading to enhanced vascular permeability generating increased interstitial pressure. The resulting vascular collapse and ischemia cause downstream hypoxia, ultimately leading to cell death and necrosis. Thus, local damage gener-ates massive amplification and tumor destruction. The tumor vasculature is readily accessed and potentially a common target irrespective of disease site in the body. Development of a therapeutic approach and particularly next generation agents benefits from effective non-invasive assays. Imaging technologies offer varying degrees of sophistication and ease of implementation. This review considers technological strengths and weaknesses with examples from our own laboratory. Methods reveal vascular extent and patency, as well as insights into tissue viability, proliferation and necrosis. Spatiotemporal resolution ranges from cellular mi-croscopy to single slice tomography and full three-dimensional views of whole tumors and measurements can be sufficiently rapid to reveal acute changes or long-term outcomes. Since imaging is non-invasive, each tumor may serve as its own control making investigations par-ticularly efficient and rigorous. The concept of tumor vascular disruption was proposed over 30 years ago and it remains an active area of research.