Tubulin Protein Research Articles

Motorless transport of microtubules along tubulin, RanGTP, and salt gradients

Microtubules are dynamic filaments that assemble spindles for eukaryotic cell division. As the concentration profiles of soluble tubulin and regulatory proteins are non-uniform during spindle assembly, we asked if diffusiophoresis - motion of particles under solute gradients - can act as a motorless transport mechanism for microtubules. We identify the migration of stable microtubules along cytoplasmic and higher concentration gradients of soluble tubulin, MgCl2, Mg-ATP, Mg-GTP, and RanGTP at speeds O(100) nm/s, validating the diffusiophoresis hypothesis. Using two buffers (BRB80 and CSF-XB), microtubule behavior under MgCl2 gradients is compared with negatively charged particles and analyzed with a multi-ion diffusiophoresis and diffusioosmosis model. Microtubule diffusiophoresis under gradients of tubulin and RanGTP is also compared with the charged particles and analyzed with a non-electrolyte diffusiophoresis model. Further, we find that tubulin and RanGTP display concentration dependent cross-diffusion that influences microtubule diffusiophoresis. Finally, using Xenopus laevis egg extract, we show that diffusiophoretic transport occurs in an active cytoplasmic environment.

How the Oocyte Nucleolus Is Turned into a Karyosphere: The Role of Heterochromatin and Structural Proteins.

Oocyte meiotic maturation includes large-scale chromatin remodeling as well as cytoskeleton and nuclear envelope rearrangements. This review addresses the dynamics of key cytoskeletal proteins (tubulin, actin, vimentin, and cytokeratins) and nuclear envelope proteins (lamin A/C, lamin B, and the nucleoporin Nup160) in parallel with chromatin reorganization in maturing mouse oocytes. A major feature of this reorganization is the concentration of heterochromatin into a spherical perinucleolar rim called surrounded nucleolus or karyosphere. In early germinal vesicle (GV) oocytes with non-surrounded nucleolus (without karyosphere), lamins and Nup160 are at the nuclear envelope while cytoplasmic cytoskeletal proteins are outside the nucleus. At the beginning of karyosphere formation, lamins and Nup160 follow the heterochromatin relocation assembling a new spherical structure in the GV. In late GV oocytes with surrounded nucleolus (fully formed karyosphere), the nuclear envelope gradually loses its integrity and cytoplasmic cytoskeletal proteins enter the nucleus. At germinal vesicle breakdown, lamin B occupies the karyosphere interior while all the other proteins stay at the karyosphere border or connect to chromatin. In metaphase oocytes, lamin A/C surrounds the spindle, Nup160 localizes to its poles, actin and lamin B are attached to the spindle fibers, and cytoplasmic intermediate filaments associate with both the spindle fibers and the metaphase chromosomes.

Lnc-Pim1 Promotes Neurite Outgrowth and Regeneration of Neuron-Like Cells Following ACR-Induced Neuronal Injury.

Decreased regenerative capacity of central nervous system neurons is the main cause for failure of damaged neuron regeneration and functional recovery. Long noncoding RNAs (lncRNAs) are abundant in mammalian transcriptomes, and many time- and tissue-specific lncRNAs are thought to be closely related to specific biological functions. The promoting effect of Pim-1 gene on neural differentiation and regeneration has been documented, but the effect and mechanism of its neighbor gene Lnc-Pim1 in regulating the response of central neurons to injury remain unclear. RT-PCR in this study demonstrated that the expression of Lnc-Pim1 was upregulated in acrylamide (ACR)-induced neuronal injury. FISH and nucleus-cytoplasmic assay demonstrated that Lnc-Pim1 was mainly expressed in the neuron cytoplasm, with a small amount in the nucleus. Western blot analysis proved that Lnc-Pim1 overexpression induced by the lentivirus vector could promote neurite outgrowth in Neuro-2a cells by activating the Erk1/2 signal pathway, and improve neurite regeneration of injured neurons by upregulating GAP-43 and β-Ⅲ tubulin protein expression. However, silencing Lnc-Pim1 expression by interfering RNA could effectively downregulate the GAP-43 and β-Ⅲ tubulin protein expression, and inhibit neurite growth of neurons. In addition, CHIRP-MS was performed to identify several potential targets of Lnc-Pim1 involved in the regulation of neurite regeneration of injured neurons. In conclusion, our study demonstrated that Lnc-Pim1 is a potential lnc-RNA, playing an important role in regulating central nerve regeneration.

NWD1 influences the extension of neuronal axons by regulating microtubule stability

Proteins belonging to the STAND (signal transduction ATPases with numerous domains) family have been implicated in crucial functions across various signal transduction pathways, encompassing both apoptosis and innate immune responses. In this study, we have identified NWD1, a member of the STAND superfamily, as a gene that regulates neurite outgrowth. This was confirmed by siRNA knockdown assay in E18 neurons. A zebrafish model was utilized to create NWD1 knockdown using the NgAgo-gDNA system, revealing the significant role of NWD1 in neurogenesis. We further revealed that NWD1 siRNA reduced the acetylated tubulin protein, and changed the ratio of soluble and polymerized tubulin. Moreover, we investigated the mechanism underlying the regulation of NWD1-mediated microtubule dynamics, and MAP1B may be a target gene. This research unveiled, for the first time, the potential role of NWD1 in regulating axon outgrowth through modulating the ratio of acetylated tubulin.

New quinoxaline-oxadiazole hybrids as tubulin inhibitors: Synthesis, cytotoxicity, and molecular dynamics simulations

This study describes the synthesis and biological evaluation of a series of novel quinoxaline-oxadiazole hybrid compounds. These compounds were designed to enhance anticancer activity through the incorporation of specific pharmacophoric groups. Structural characterization using NMR and HRMS spectroscopy confirmed the successful synthesis of the hybrids. Cytotoxicity assays revealed that several compounds exhibited significant activity against various cancer cell lines. Compounds 8a and 8f demonstrated potent activity against A549 cells, while 8a, 8b, and 8c were effective against HaCaT cells. Additionally, compounds 8i and 8a showed activity against HepG2 cells. Molecular docking and dynamics simulations suggested that compounds 8c and 8d bind strongly to the tubulin protein, a target for anticancer drugs. These compounds exhibited binding affinities comparable to known anticancer compounds. The results of this study highlight the potential of quinoxaline-oxadiazole hybrids, especially those with halogen substitutions, as promising candidates for the development of novel anticancer therapeutics.

Synthesis, Fluorescence Properties, Molecular Docking Studies, and Analysis of the Crystalline Structure of the Novel 5‐Imino‐7‐Aryl‐5H‐Thiazolo[3.2‐a]Pyrimidine‐6‐Carbonitrile and Its Derivatives

ABSTRACTThis study describes a simple, inexpensive, and effective method for the synthesis of new 5‐imino‐7‐aryle‐5H‐thiazolo[3,2‐a]pyrimidine‐3‐carbonitrile derivatives 4a‐e using a green procedure that does not require the use of heat or a base, creating a strategy that meets both economic and environmental demands. Various synthesized products were characterized via diverse techniques such as 1H‐NMR, infrared (FT‐IR), Mass spectroscopy (MS), and single crystal X‐ray diffraction. Using a fluorescence spectrometer, the 5‐imino‐7‐phenyle‐5H‐thiazolo[3.2‐a]pyrimidine‐3‐carbonitrile 4a has been tested as a potent fluorescent agent in mixture of DMSO/Water at 10−4 M in one hand, and on the other hand the results of our fluorescence evaluation studies with metal ions (Pb(II), Ba(II), Cd(II), Ni(II), Mn(II), Hg(II), Zn(II), Fe(II), Co(II), Cu(II), La(II), Cr(III), and Fe(III)) have shown that this compound exhibits a turn‐on and turn‐off of the fluorescence to 4a compound with these metals, what forms poor to good interaction by these ions. This result represents the emergence of a new potential ligand for the two heavy cations Cd(II) and Pb(II), which are toxic and polluting, and whose detection is currently of high interest. As well, In the molecular docking evaluation study, it was determined that the 4e molecule has an exceptional ability to inhibit the binding energy of the tubulin protein by −9.13 kcal/mmol, compared to other compounds. The results demonstrate the possibilities for a novel oral medication application.

A potent Bioorganic azapodophyllotoxin derivative Suppresses tumor Progression in Triple negative breast Cancer: An Insight into its Inhibitory effect on tubulin polymerization and Disruptive effect on microtubule assembly

Triple negative breast cancer (TNBC) has long been a challenging disease owing to its high aggressive behaviour, poor prognosis and its limited treatment options. The growing demand of new therapeutics against TNBC enables us to examine the therapeutic efficiency of an emerging class of anticancer compounds, azapodophyllotoxin derivative (HTDQ), a nitrogen analogue of podophyllotoxin, using different biochemical, spectroscopic and computational approaches. The anticancer activities of HTDQ are studied by performing MTT assay in a dose depended manner on Triple negative breast cancer cells using MDA–MB-468 and MDA-MB-231 cell lines with IC50 value 937 nM and 1.13 µM respectively while demonstrating minimal effect on normal epithelial cells. The efficacy of HTDQ was further tested in 3D tumour spheroids formed by the human TNBC cell line MDA-MB468 and also the murine MMTV positive TNBC cell line 4 T1. The shrinkage that observed in the tumor spheroid clearly indicates that HTDQ remarkably decreases the growth of tumor spheroid thereby affirming its cytotoxicity. The 2D cell viability assay shows significant morphological alteration that possibly caused by the cytoskeleton disturbances. Hence the binding interaction of HTDQ with cytoskeleton protein tubulin, its effect on tubulin polymerisation as well as depolymerisation of preformed microtubules along with the conformational alternation in the protein itself have been investigated in detail. Moreover, the apoptotic effects of HTDQ have been examined using a range of apoptotic markers. HTDQ-treated cancer cells showed increased expression of cleaved PARP-1 and pro-caspase-3, suggesting activation of the apoptosis process. HTDQ also upregulated pro-apoptotic Bax expression while inhibiting anti-apoptotic Bcl2 expression, supporting its ability to induce apoptosis in cancer cells. Hence the consolidated biochemical and spectroscopic research described herein may provide enormous information to use azapodophyllotoxin as promising anticancer therapeutics for TNBC cells.

Microtubules and cardiovascular diseases: insights into pathology and therapeutic strategies

Microtubules, complex cytoskeletal structures composed of tubulin proteins in eukaryotic cells, have garnered recent attention in cardiovascular research. Investigations have focused on the post-translational modifications of tubulin, including acetylation and detyrosination. Perturbations in microtubule homeostasis have been implicated in various pathological processes associated with cardiovascular diseases such as heart failure, ischemic heart disease, and arrhythmias. Thus, elucidating the intricate interplay between microtubule dynamics and cardiovascular pathophysiology is imperative for advancing preventive and therapeutic strategies. Several natural compounds have been identified to potentially modulate microtubules, thereby exerting regulatory effects on cardiovascular diseases. This review synthesizes current literature to delineate the roles of microtubules in cardiovascular diseases and assesses the potential of natural compounds in microtubule-targeted therapies.

Tubulin Vibration Modes Are in the Subterahertz Range, and Their Electromagnetic Absorption Is Affected by Water.

Many proteins are thought to coordinate distant sites in their structures through a concerted action of global structural vibrations. However, the direct experimental spectroscopic detection of these vibration modes is rather elusive. We used normal-mode analysis to explore the dominant vibration modes of an all-atom model of the tubulin protein and described their characteristics using a large ensemble of tubulin structures. We quantified the frequency range of the normal vibrational modes to be in the subterahertz band, specifically between ∼40 and ∼160 GHz. Adding water layers to the model increases the frequencies of the low-frequency modes and narrows the frequency variations of the modes among the protein ensemble. We also showed how the electromagnetic absorption of tubulin vibration modes is affected by vibrational damping. These results contribute to our understanding of tubulin's vibrational and electromagnetic properties and provide a foundation for future attempts to control protein behavior via external electromagnetic fields.

Exploring highly selective polymethoxy fenamate isosteres as novel anti-prostate cancer agents: Synthesis, biological activity, molecular docking, molecular dynamics, and ADME studies

In this study, we synthesized and characterized sixteen new polymethoxy-substituted hydrazone derivatives. These compounds were evaluated for their in vitro cytotoxic activity against human prostate cancer (PC3) and human umbilical vein endothelial (HUVEC) cell lines. Compounds 5, 6, 7, and 11 exhibited significant cytotoxic effects with high selectivity index. Molecular docking studies and MM-GBSA binding free energy calculations were performed against tubulin protein. Compound 7 emerged as a particularly promising candidate, displaying an IC50 value of 1.49 µM against PC3 cells and a selectivity index of 264. Compound 7 achieved impressive docking score -13.655 kcal/mol against tubulin and formed stable hydrogen bonds and π-π stacking interactions with key residues in this protein. MD simulations confirmed the stability of the 7-tubulin complex. ADME analysis indicated that compound 7 has favorable absorption, solubility, and permeability properties, with minimal rule violations. The SAR analysis highlighted the significance of specific functional groups in enhancing the compound's cytotoxic and binding properties. Overall, compound 7 is identified as a leading candidate due to its exceptional cytotoxicity, high selectivity index, strong binding affinities, and favorable pharmacokinetic profile, making it a top candidate for further investigation and development as a novel anticancer agent.

Evaluating some new benzimidazole derivative: Insilico docking studies for anthelmintic drug development

The Heterocyclic compounds used as medicinal agents in the field of study since long time. Benzo-fused heterocyclic nucleus benzimidazole founds significant class for new drug development. Molecular docking study is a technique in Computer Aided Drug Designing for studying ligand and protein interaction. The main motto of this work is to perform Preliminary screening using SAR studies, OSIRIS molecular property explorer, PASS Prediction Activity spectra and Rule of Five and to check the proposed benzimidazole compounds are potentially active as Anthelminthic agent by Docking studies with beta tubulin protein (PDB ID 1OJ0) using Auto dock 1.5.6 and VINA. Among all proposed benzimidazole derivatives, 4-((1H-benzimidazol-1-ylimino) methyl) phenol (5d) is the most effective and showed maximum binding energy (−7.4 K/Cal) when compared with standard drug albendazole (−7.1 K/Cal).

Cryo-electron tomography elucidates annular intraluminal configurations in Caenorhabditis elegans microtubules.

Microtubules serve as integral components in cellular operations such as cell division, intracellular trafficking, and cellular architecture. Composed of tubulin protein subunits, these hollow tubular structures have been increasingly elucidated through advanced cryo-electron microscopy (Cryo-EM), which has unveiled the presence of microtubule inner proteins (MIPs) within the microtubular lumen. In the present investigation, we employ a synergistic approach incorporating high-pressure freezing, cryo-focused ion beam milling, and Cryo-electron tomography (Cryo-ET) to interrogate the in situ architecture of microtubules in Caenorhabditis elegans larvae. Our Cryo-ET assessments across neuronal cilia and diverse tissue types consistently demonstrate the formation of annular configurations within the microtubular lumen. In concert with recently characterized MIPs, our in situ observations within a living organism corroborate the hypothesis that intricate luminal assemblages exist within microtubule scaffolds. These findings necessitate further exploration into the molecular constituents and functional ramifications of these internal microtubular configurations in both cellular physiology and pathophysiology.

Immunodetection of tubulin and centromeric histone H3 (CENH3) proteins in Glycine species.

The centromeres appear as primary constrictions on monocentric metaphase chromosomes; where sister chromatids are held together and assemble the proteinaceous kitechore complex at which microtubule proteins attach during nuclear divisions for pulling sister chromatids to opposite cell poles. The movement of chromosomes is usually governed by structural proteins that are either species-specific or highly conserved, such as the centromere-specific histone H3 (CENH3) and tubulin proteins, respectively. We aimed to detect these proteins across eight different Glycine species by an immunofluorescence assay using specific antibodies. Furthermore, with the α-tubulin antibody we traced the dynamics of microtubules during the mitotic cell cycle in Glycine max. With two-color immunofluorescence staining, we showed that both proteins interact during nuclear division. Finally, we proved that in different diploid and tetraploid Glycine species CENH3 can be detected in functional centromeres with spatial proximity of microtubule proteins.

Sphingolipid inhibitor response gene GhMYB86 controls fiber elongation by regulating microtubule arrangement.

Although the cell membrane and cytoskeleton play essential roles in cellular morphogenesis, the interaction between the membrane and cytoskeleton is poorly understood. Cotton fibers are extremely elongated single cells, which makes them an ideal model for studying cell development. Here, we used the sphingolipid biosynthesis inhibitor, fumonisin B1 (FB1), and found that it effectively suppressed the myeloblastosis (MYB) transcription factor GhMYB86, thereby negatively affecting fiber elongation. A direct target of GhMYB86 is GhTUB7, which encodes the tubulin protein, the major component of the microtubule cytoskeleton. Interestingly, both the overexpression of GhMYB86 and GhTUB7 caused an ectopic microtubule arrangement at the fiber tips, and then leading to shortened fibers. Moreover, we found that GhMBE2 interacted with GhMYB86 and that FB1 and reactive oxygen species induced its transport into the nucleus, thereby enhancing the promotion of GhTUB7 by GhMYB86. Overall, we established a GhMBE2-GhMYB86-GhTUB7 regulation module for fiber elongation and revealed that membrane sphingolipids affect fiber elongation by altering microtubule arrangement.

Combination of dual JAK/HDAC inhibitor with regorafenib synergistically reduces tumor growth, metastasis, and regorafenib-induced toxicity in colorectal cancer

BackgroundTreatment with regorafenib, a multiple-kinase inhibitor, to manage metastatic colorectal cancers (mCRCs) shows a modest improvement in overall survival but is associated with severe toxicities. Thus, to reduce regorafenib-induced toxicity, we used regorafenib at low concentration along with a dual JAK/HDAC small-molecule inhibitor (JAK/HDACi) to leverage the advantages of both JAK and HDAC inhibition to enhance antitumor activity. The therapeutic efficacy and safety of the combination treatment was evaluated with CRC models.MethodsThe cytotoxicity of JAK/HDACi, regorafenib, and their combination were tested with normal colonic and CRC cells exhibiting various genetic backgrounds. Kinomic, ATAC-seq, RNA-seq, cell cycle, and apoptosis analyses were performed to evaluate the cellular functions/molecular alterations affected by the combination. Efficacy of the combination was assessed using patient-derived xenograft (PDX) and experimental metastasis models of CRC. To evaluate the interplay between tumor, its microenvironment, and modulation of immune response, MC38 syngeneic mice were utilized.ResultsThe combination therapy decreased cell viability; phosphorylation of JAKs, STAT3, EGFR, and other key kinases; and inhibited deacetylation of histone H3K9, H4K8, and alpha tubulin proteins. It induced cell cycle arrest at G0-G1 phase and apoptosis of CRC cells. Whole transcriptomic analysis showed that combination treatment modulated molecules involved in apoptosis, extracellular matrix-receptor interaction, and focal adhesion pathways. It synergistically reduces PDX tumor growth and experimental metastasis, and, in a syngeneic mouse model, the treatment enhances the antitumor immune response as evidenced by higher infiltration of CD45 and cytotoxic cells. Pharmacokinetic studies showed that combination increased the bioavailability of regorafenib.ConclusionsThe combination treatment was more effective than with regorafenib or JAK/HDACi alone, and had minimal toxicity. A clinical trial to evaluate this combination for treatment of mCRCs is warranted.

Nanoparticle-assisted tubulin assembly is environment dependent

Nanomaterials acquire a biomolecular corona upon introduction to biological media, leading to biological transformations such as changes in protein function, unmasking of epitopes, and protein fibrilization. Ex vivo studies to investigate the effect of nanoparticles on protein-protein interactions are typically performed in buffer and are rarely measured quantitatively in live cells. Here, we measure the differential effect of silica nanoparticles on protein association in vitro vs. in mammalian cells. BtubA and BtubB are a pair of bacterial tubulin proteins identified in Prosthecobacter strains that self-assemble like eukaryotic tubulin, first into dimers and then into microtubules in vitro or in vivo. Förster resonance energy transfer labeling of each of the Btub monomers with a donor (mEGFP) and acceptor (mRuby3) fluorescent protein provides a quantitative tool to measure their binding interactions in the presence of unfunctionalized silica nanoparticles in buffer and in cells using fluorescence spectroscopy and microscopy. We show that silica nanoparticles enhance BtubAB dimerization in buffer due to protein corona formation. However, these nanoparticles have little effect on bacterial tubulin self-assembly in the complex mammalian cellular environment. Thus, the effect of nanomaterials on protein-protein interactions may not be readily translated from the test tube to the cell in the absence of particle surface functionalization that can enable targeted protein-nanoparticle interactions to withstand competitive binding in the nanoparticle corona from other biomolecules.

3D-QSAR, molecular docking, ADMET, simulation dynamic, and retrosynthesis studies on new styrylquinolines derivatives against breast cancer

Abstract Breast cancer is the most common illness among women, accounting for 25% of all diagnoses, as stated by the American Cancer Society. Current research focuses on 43 compounds of styrylquinoline derivatives as potential inhibitors of tubulin to design a new drug that could potentially be effective against breast cancer cells in humans. The target compounds were subjected to a three-dimensional quantitative structure-activity relationship/comparative molecular similarity indices analysis (CoMSIA) approach, where CoMSIA models were used; the best results obtained are (Q 2 = 0.84, R 2 = 0.97, r ext 2 {r}_{\text{ext}}^{2} = 0.91), H-bond acceptor field was discovered to be important for increasing inhibitory activity by examining the contour maps (54%), and it plays a key role in the prediction of anticancer activity. Based on the contour maps of the CoMSIA models, we obtained information that allows us to propose four new molecules with higher cancer inhibitory than the 43 compounds found in the literature. The molecular docking was applied to determine the likely types of binding between the tubulin protein (PDB ID: 4O2B) and the proposed compounds, and the results show that M1 has a higher total score of 6.53 and two interactions with important conventional hydrogen bond type, followed by compound M2 with a total score of 5.74. Furthermore, the designed molecules showed better pharmacokinetic properties based on absorption, distribution, metabolism, excretion, and toxicity properties. Molecular dynamics simulations at 100 ns were conducted to confirm the binding stability of the selected ligands (M1 and M2) with tubulin protein. The simulation parameters used in the current study are root mean square deviation, root mean square fluctuation, H-bond, Rg, solvent accessible surface area, and binding energy. As a result, the designed compounds (ligands M1 and M2) have shown noteworthy potential as a drug candidate for experimental in vivo and in vitro testing due to their potential inhibition of breast cancer. Finally, the study of retrosynthesis in this work facilitates the synthesis of drug candidates.

Oxindoline Containing Thiazolidine‐4‐one Tethered Triazoles Act as Antimitotic Agents by Targeting Microtubule Dynamics

AbstractOxindoline containing thiazolidine‐4‐ones linked triazole hybrids (24 a–l) series were synthesized by multistep synthesis and tested for their cytotoxic activity against four human cancer cell lines. Significantly higher susceptibility was observed in liver (HepG2) cancer cells. Among them conjugates 24 c and 24 e exhibited promising cytotoxicity with IC50 values of 1.64 μM, and 2.07 μM respectively when compared to the standard 5‐fluorouracil (IC50=20.8 μM) against the HepG2 cell line. Later on, these compounds changed the morphology of HepG2 cells and significantly inhibited colony formation in HepG2 in a dose‐dependent manner. The scratch assay divulged that these compounds decreased wound size and inhibited cell migration. Interestingly, they induced the cell cycle arrest at the S phase. Moreover, the DCFDA assay indicated ROS production proportionate to compound dose and AO/Eb staining revealed increased apoptotic cell count with higher doses. The tubulin polymerization assay reveals that they inhibited the microtubules and acted as antimitotic agents. In‐silico results of these conjugates also support their tubulin inhibitory properties. Interestingly, these compounds have adequate ADME‐toxicity parameters. Based on free energy calculation results, it was observed that these inhibitors influence the conformational flexibility of the target tubulin protein.

Anticancer activity of 4α-(cyclopropyl formylpiperazinyl)-4-deoxypodophyllotoxin and its mechanism of action

Podophyllotoxin (PPT) is a naturally occurring lignan extracted from the rhizomes of the Podophyllum plant. It exhibits toxicity towards a broad spectrum of cancer cells and can induce cell death by inhibiting the polymerization of microtubule proteins. In our pursuit of more potent anticancer drug candidates, 4α-(cyclopropyl formylpiperazinyl)-4-deoxypodophyllotoxin (GHGT-17) was successfully synthesized by introducing a piperazine group, formyl group, and cyclopropyl group at the C-4 position of PPT. The activity of GHGT-17 against various types of cancer cells was evaluated using the MTT assay. It exhibited significant potency against lung cancer cells, with IC50 values of 0.080 ± 0.020 μM (A549) and 0.086 ± 0.004 μM (H460), without obvious toxicity towards lung epithelial cells 16HBE (IC50 > 100 μM). Further investigations demonstrated that GHGT-17 induced morphological changes in A549 and H460 cells, inhibited proliferation in a time- and dose-dependent manner. Furthermore, GHGT-17 inhibited the formation of cell colonies in a dose-dependent manner. It was found to inhibit cell migration, arrest the cell cycle in the G2/M phase, induce nuclear wrinkling, decrease mitochondrial membrane potential, and inhibit microtubule protein polymerization. These effects ultimately contribute to the induction of endogenous apoptosis. In silico studies, ADMET analysis revealed that GHGT-17 exhibited a satisfactory bioavailability with good water solubility, easy absorption, and well-proportioned distribution in the body. Molecular docking was performed to predict the binding mode and interactions of GHGT-17 with tubulin protein (1SA0). Additionally, GHGT-17 was submitted to molecular dynamics simulation and RMSD, RMSF, Rg, hydrogen bonding was analyzed. The complex showed a rather low binding free energy (−36.37 kJ mol−1) and thus exhibited a superior binding affinity towards to tubulin protein. In summary, the combined results indicated that GHGT-17 exhibits promise as a prospective potential novel drug candidate worthy of further investigation for its potential application in lung cancer therapy.

Damage-repair events increase the instability of cortical microtubules in Arabidopsis.

Microtubules rely on dynamic assembly and disassembly for their functions. Increasing evidences support that the damage-repair of microtubule lattices can affect microtubule dynamics in vitro and in animal cells. Here we successfully established a way for visualizing damage-repair sites on microtubule lattices in plant cells, via labeling the tubulin proteins with the photoconvertible fluorescent protein mEOS3.2. We observed that the crossovers of the microtubule lattice were more prone to be damaged and repaired, with the frequency of damage-repair events positively correlated with the crossing angle between microtubules. The microtubules with damage-repair events displayed shorter lifespans and significantly increased severing frequency compared with the undamaged microtubules. These observations suggested that the damage-repair events promoted instability of cortical microtubules in plant cells.