B cell activation requires the formation of an immune synapse (IS), where coordinated cytoskeletal remodeling and organelle dynamics enable antigen extraction and presentation. While mitochondria are known to regulate cellular metabolism during activation, their role in IS function remains poorly understood. Here, we investigated how mitochondrial dynamics influence antigen processing and presentation in B cells. We show that B cell receptor (BCR) engagement induces rapid phosphorylation of the mitochondrial fission GTPase Drp1 at Ser616. Treatment with mdivi-1, a compound used to perturb Drp1-associated mitochondrial fission that can also affect mitochondrial complex I activity, altered mitochondrial morphology, reduced mitochondrial activity, and decreased their stable accumulation at the synapse. This was accompanied by increased tubulin acetylation, lysosome retention near the MTOC, and reduced delivery to the synaptic membrane. Accordingly, lysosome fusion, antigen extraction, and presentation to T cells were significantly diminished in mdivi-1-treated B cells. Together, our findings suggest that mdivi-1-sensitive mitochondrial fission and activity are associated with mitochondrial positioning, lysosomal trafficking, and exocytosis at the B cell immune synapse, supporting a model in which mitochondrial dynamics contribute to efficient antigen extraction and presentation.

H-ABC tubulinopathy exhibits a cytoskeletal defect associated with microtubule stability.

Microtubules are essential cytoskeleton polymers composed of α/β-tubulin heterodimers that play a central role in the regulation of various cellular processes, including cell division, cell shape, cell polarity, motility and intracellular trafficking. The expression of different tubulin genes results in a variety of isotypes that, combined with post-translational modifications (PTMs), define a "tubulin code" that generates microtubule diversity. Growing evidence has shown promising links between tubulin isotypes and PTMs with several cancer properties, leading to the emergence of the concept of a "cancer tubulin code". In this review, we focus on dissecting the impact of tubulin acetylation, detyrosination and polyglutamylation on microtubule properties and functions, and how these PTMs, together with specific tubulin isotypes, affect cancer cell division, invasion and metastasis. Because conventional chemotherapy with microtubule-targeting drugs often leads to resistance and accounts for a high mortality rate among cancer patients, we discuss possible directions that explore the potential of the cancer tubulin code and respective microtubule diversity in improving drug response, while overcoming resistance. Lastly, we address the therapeutic value of small-molecule inhibitors of tubulin-modifying enzymes in cancer treatment. Overall, this review showcases the potential of exploring the cancer tubulin code to open new avenues in diagnostic, prognostic and therapeutic applications for precision oncology.

ABSTRACTCytoplasmic inclusions containing TAR DNA‐binding protein 43 kDa (TDP‐43) are recognized as a major pathological feature of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Peptidyl‐prolyl cis‐trans isomerase A (PPIA) interacts with TDP‐43 and influences its aggregation and function. This interaction is facilitated by PPIA Lys‐acetylation. Here, we investigated whether restoring lysine acetylation homeostasis exerts protective effects on TDP‐43 proteinopathy in vitro and in vivo and how this relates with PPIA. We found that vorinostat/SAHA, a broad‐spectrum histone deacetylase (HDAC) inhibitor that increases PPIA acetylation, is able to reverse TDP‐43 mislocalization in a cellular model of TDP‐43 proteinopathy. We confirmed its effects in peripheral blood mononuclear cells from ALS patients and explored its impact on TDP‐43 proteinopathy and PPIA acetylation in the Thy1‐hTDP‐43 mouse model. Thy1‐hTDP‐43 mice treated with SAHA showed a delayed onset of TDP‐43 pathology, associated with PPIA nucleus‐cytoplasm redistribution, lower neurodegeneration and neuroinflammation, and improved neuromuscular function markers. However, these effects were transient. When combined with arimoclomol, a heat shock protein co‐inducer, a mitigation of the neurodegeneration was sustained. A synergistic effect was observed in periphery, greatly enhancing tubulin acetylation and reducing phosphorylated TDP‐43 accumulation in the sciatic nerve and acetylcholine receptor γ‐subunit expression in gastrocnemius muscle. This study suggests that HDAC inhibition could be beneficial in restoring TDP‐43 localization and function through multiple mechanisms, including modulation of PPIA acetylation. The combination of lysine deacetylation inhibition and arimoclomol shows a synergistic effect in vivo and has potential as a therapeutic approach for patients.

ABSTRACTCell-matrix adhesion regulates membrane trafficking, Golgi organization, and function. Altered Golgi organization in cancer cells may influence trafficking and cargo processing. A simple screen revealed distinct, adhesion-dependent differences in Golgi organization across breast (MDAMB231 versus MCF7) and lung (A549 versus CaLu1) cancer cell lines. To identify regulators driving these differences, we performed an in silico analysis of differentially expressed genes in the Cancer Cell Line Encyclopedia dataset, integrating Golgi-associated functions from interaction networks and literature. This analysis highlighted AXL as a putative Golgi regulator. AXL is prominently localized to the Golgi and is displaced upon inhibition with R428, which disrupts Golgi organization. AXL knockdown also does the same. AXL-mediated regulation of the Golgi is adhesion dependent. Mechanistically, AXL controls Arf1 activation through an AMPK-GBF1 pathway. Targeting of AMPK activation thus significantly reverses R428-mediated Golgi disorganization. Loss of adhesion promotes AMPK and reduces Arf1 activity, displacing AXL and Arf1 from the Golgi, driving its disorganization. This impacts Golgi-associated functions, tubulin acetylation in MDAMB231 cells, and cell-surface glycosylation in A549 cells. Together, our findings identify an adhesion-AXL-AMPK-GBF1-Arf1 pathway governing Golgi organization and function in cancer cells.

Aluminum exposure impairs nuclear envelope breakdown for mouse zygote formation.

Tubulin post-translational modifications regulate microtubule dynamics. Although α-tubulin acetylation has been linked to microtubule stability, how this modification affects the overall organization of cellular microtubules remains obscure. Here, we generated a Chlamydomonas mutant lacking the acetyltransferase αTAT1, which completely abolished α-tubulin K40 acetylation. Surprisingly, the steady-state lengths of normally acetylated structures, axonemes, and rootlets were largely unaffected. αTAT1 was found to localize to the ciliary tip, where it may stabilize the distal axoneme. Consistent with this, loss of acetylation caused an increase in axonemal tubulin turnover, as revealed by dikaryon-fusion assays. Unexpectedly, the atat1-1 mutant displayed an increased number of dynamic cortical microtubules and could regenerate long cilia after amputation, even when protein synthesis was inhibited. Notably, this increase in cortical microtubules required the presence of cilia, as the atat1-1 mutant carrying the ift46-1 mutation, which abolishes ciliogenesis, exhibited normal cortical microtubule levels. Despite these dramatic cytoskeletal changes, cell growth and division remained essentially normal. These findings suggest that acetylation modulates microtubule behavior by regulating axonemal tubulin turnover and cytoplasmic microtubule dynamics, while cellular morphology is buffered against variations in microtubule content.

A functional nervous system depends on neuronal morphology established during differentiation. The microtubule (MT) cytoskeleton supports neuronal differentiation by organizing organelle positioning and facilitating transport. The dynamics and properties of MTs are regulated by a variety of post-translational modifications (PTMs), with many organelle interactions occurring preferentially on modified MTs. Here we find that tubulin acetylation is enriched at specific subcellular locations during differentiation of human induced neurons. We apply a quantitative multispectral imaging pipeline to simultaneously analyze eight membrane-bound organelles and define how tubulin acetylation reshapes organelle architecture and interaction networks during neuronal differentiation. We find that loss of tubulin acetylation broadly alters organelle morphology, spatial distribution, and inter-organelle interactions, with lysosome-organelle interactions most affected. Loss of acetylated MTs leads to enlarged, highly acidified lysosomes, impaired lysosomal fission, and accumulation of autolysosomes, consistent with defective lysosomal reformation. Super-resolution microscopy further reveals that lysosome-endoplasmic reticulum (ER) contacts preferentially associate with acetylated MTs. Together, our data support a model in which tubulin acetylation coordinates lysosome-ER interactions to facilitate lysosome remodeling and turnover. This work establishes tubulin acetylation as a key cytoskeletal regulator that links organelle interactions to organelle homeostasis important for neuronal differentiation.

Histone deacetylase 6 (HDAC6) inhibitors have shown effectiveness in preclinical models of chemotherapy-induced peripheral neuropathy (CIPN), a severe side effect of various antineoplastic drugs, with no available preventive or therapeutic treatments. This study presents in vivo results for ITF6464 and ITF6475, 2 HDAC6 inhibitors featuring a difluoromethyloxadiazole (DFMO), zinc-binding group ensuring selectivity for HDAC6. This study investigated the potential effect of 2 new selective DFMO HDAC6 inhibitors in preventive and curative settings in a well-established CIPN model. The effectiveness of treatments was evaluated by dynamic test and histological analysis on dorsal root ganglia (DRG) and skin biopsy. The acetylation of tubulin was also investigated in sciatic nerve by western blot. ITF6464 and ITF6475 administered at 12.5 mg/kg dose prevented cisplatin-induced mechanical allodynia (***P < 0.001 and **P < 0.01, respectively). Histologically, both ITF6464 and ITF6475 at all doses prevented damage in DRGs. ITF6464 at 6 mg/kg and ITF6475 at 1 mg/kg protected intraepidermal nerve fibers (IENF) from cisplatin-induced damage (*P < 0.05). After 2 cisplatin cycles, ITF6475 12.5 mg/kg was effective in reverting mechanical allodynia (***P < 0.001). ITF6475 reverted cisplatin-induced damage in DRGs and, at the highest dose, also reverted IENF damage (○○ P < 0.01). Cisplatin induced a reduction in acetylated tubulin in the sciatic nerve of mice, and ITF6464 and ITF6475 at 12.5 mg/kg dose were able to significantly revert this condition. These studies highlight the potential of the new selective HDAC6 inhibitors ITF6464 and ITF6475 as promising treatments for CIPN.

Integrin-mediated adhesion regulates cellular survival and mechanotransduction, processes often deregulated in cancers. During breast tumor progression, matrix stiffening influences cytoskeletal organization, although its effect on organelle organization and function remains unclear. Here, we examine how Golgi organization responds to matrix stiffness sensing in breast cancer cells. In adherent MDA-MB-231 cells, the Golgi becomes progressively more compact and organized with increasing matrix stiffness, accompanied by enhanced tubulin acetylation, indicating stiffness-dependent regulation. In contrast, MCF7 cells display a diffused or disorganized Golgi regardless of matrix stiffness. AXL, a receptor tyrosine kinase differentially expressed in MDA-MB-231 cells and absent in MCF7, localizes prominently to the Golgi. Inhibition or knockdown of AXL disrupted stiffness-dependent Golgi organization in MDA-MB-231 cells, whereas stable AXL expression in MCF7 restored Golgi organization at higher stiffness. A stiffness-dependent increase in AXL and Arf1 expression regulates Arf1 activation and localization to control mechanosensitive Golgi organization. Inhibition of AXL and/or Arf1 disrupted Golgi organization, tubulin acetylation and cell-surface glycosylation. Together, our findings reveal a mechanoresponsive AXL-Arf1-Golgi signaling axis that integrates matrix stiffness sensing with Golgi organization and function in breast cancer cells.

Post-translational modifications (PTMs) of tubulin regulate microtubule properties and functions. The Verhey lab created recombinant monoclonal antibodies (rMAbs) against tubulin acetylation (rMAb-6-11B-1), tyrosinated α-tubulin (rMAb-YL1/2), and glutamylation (rMAb-GT335) (Blasius et al., 2025; Hotta et al., 2026). Here, we validate these rMAbs in C. elegans hermaphrodites and males. These rMAbs faithfully reproduce the reported cell-type-specific staining patterns of commercial antibodies, providing high-quality, cost-effective resources for studying the tubulin code.

Post-translational modifications of microtubules regulate their stability and dynamics. Acetylation of tubulin at lysine 40 (K40) by -acetyltransferase (TAT) occurs on the luminal side of microtubules, stabilizes their structure, and plays essential roles in various cellular processes across eukaryotes. Apicomplexan parasites include the malaria-causing Plasmodium species and Toxoplasma gondii, both of which possess unusually stable subpellicular microtubules, a set of cytoskeletal filaments underlying the parasite’s inner membrane complex. Interestingly, while Toxoplasma gondii and human-infecting Plasmodium species retain both K40 and TAT, rodent-infecting Plasmodium species have lost TAT, and K40 has been replaced by glutamine (Q40), a residue that can mimic acetylated lysine. Here, we investigate the role of microtubule acetylation in apicomplexan parasites by generating and characterizing genetic mutants in Plasmodium berghei and Toxoplasma gondii. In Plasmodium berghei, introduction of a Q40K mutation in 1 tubulin did not affect parasite development or infectivity, suggesting that the absence of K40 acetylation is not detrimental. In Toxoplasma gondii, we confirmed that TAT is responsible for microtubule acetylation but, contrary to previous reports, its deletion had no impact on parasite growth in vitro. Together, these results indicate that luminal K40 acetylation is not essential for microtubule function in either species, pointing to functional redundancy and highlighting the plasticity of cytoskeletal regulation in apicomplexan parasites.

Kinesin-3 UNC-104(KIF1A) is the major anterograde axonal transporter of synaptic vesicles and is expressed pan-neuronally. Genetic defects in this molecular motor are linked to KIF1A-associated neurological disorders (KAND), a spectrum of severe neurological conditions encompassing Charcot-Marie-Tooth (CMT) disease and hereditary spastic paraplegia (HSP). From a candidate screen for genes causing neurotransmission defects in C. elegans and simultaneously affecting post-translational modification of tubulin, we identified allele unc-17(e245) significantly elevating tubulin acetylation invitro and invivo. UNC-17 encodes for a VAChT (vesicular acetylcholine transporter) and its human ortholog SLC18A3 is implicated in Alzheimer's and Huntington's disease. To exclude secondary effects of the unc-17 mutation, we tracked UNC-104 and RAB-3 motility in the non-cholinergic ALM neuron. With upregulated tubulin acetylation in ALM (anterior lateral microtubule) neurons in unc-17(e245) strains (visualized by immunostaining), motility of both motor and its cargo is significantly compromised. However, motility of UNC-104 improves when knocking down α-tubulin acetyltransferase MEC-17(ATAT1) in unc-17(e245) strains and, conversely, is negatively affected when overexpressing MEC-17 in wild type animals. Similar effects were observed in cholinergic sublaterals. UNC-17 and UNC-104 colocalize in cholinergic head neurons, consistent with a motor-cargo relationship. Strikingly, mec-17 knockdown significantly decreases their colocalization, while unc-17 knockdown reduces UNC-104/MEC-17 colocalization in head neurons. Direct protein-protein interactions were validated through bimolecular fluorescence complementation (BiFC) and co-immunoprecipitation (Co-IP) assays. In both assays, mec-17 knockdown significantly reduced the UNC-104/UNC-17 associations, whereas unc-17 knockdown significantly diminished UNC-104/MEC-17 interactions. These findings indicate a tripartite regulatory complex UNC-104/UNC-17/MEC-17. We propose that unc-17 knockdown disrupts sequestration of MEC-17 within this complex and that the release of MEC-17 results in increased tubulin acetylation. Resulting elevated tubulin acetylation suppresses UNC-104 motor processivity and cargo transport efficiency.

Tubulin-aldose reductase-Na+/K+-ATPase axis in diabetes: Molecular mechanisms and new pharmacological perspectives.

Histone deacetylase inhibitors are known to influence memory consolidation, with synaptic protein acetylation playing a crucial role in plasticity processes such as long-term potentiation (LTP). In this study, we explored the role of non-histone protein acetylation in the consolidation of long-term inhibitory avoidance (IA) memory. We found that the histone deacetylase 6 (HDAC6) inhibitor, Tubastatin A, significantly enhanced memory consolidation when administered either intraperitoneally or directly into the hippocampus immediately after memory acquisition, but not when administered three hours later. Tubastatin A also preserved tubulin acetylation in hippocampal extracts in vitro and induced an increase in acetylation levels in vivo. Training in the IA task led to alterations in tubulin acetylation within synaptic extracts, specifically at residues other than lysine 40 of α-tubulin, accompanied by changes in synaptic composition. Furthermore, chemical LTP in primary hippocampal neuron cultures increased dendritic and synaptic acetylation, as well as the density of PSD95 clusters. These findings establish a role for HDAC6 in modulating tubulin acetylation during memory consolidation and provide new insights into the broader significance of non-histone protein acetylation in memory formation.

Microtubules (MTs) form dynamic cytoskeletal scaffolds essential for intracellular transport, organelle positioning, and spatial organization of signaling. Their architecture and function are continuously remodeled through the concerted actions of microtubule-associated proteins (MAPs), post-translational modifications (PTMs), and molecular motors. To precisely interrogate these processes in living systems, we developed a genetically encoded optogenetic toolkit for spatiotemporal control of MT organization and dynamics. By replacing native multimerization motifs with a blue light-responsive oligoermization domain, we have engineered single-component probes, OptoMT and OptoTIP, that reversibly label MT polymers or track plus-ends with tunable kinetics from seconds to minutes. When coupled to enzymatic effectors, these modules enable localized tubulin acetylation or detyrosination, directly linking PTMs to MT stability. We further engineered OptoMotor, a light-activatable kinesin platform that reconstitutes tail-dependent cargo transport along MTs, and OptoSAW, a light-triggered severing actuator for controlled MT disassembly. Using these tools, we reveal how local MT integrity governs lysosomal trafficking and ER-associated signaling dynamics. Collectively, this versatile single-component toolkit bridges molecular design with cytoskeletal function, offering new avenues to illuminate how dynamic cytoskeletal architectures coordinate intracellular organization, transport, and signaling.

Dysregulated proteostasis and intracellular transport contribute to neurodegeneration. Histone deacetylase 6 (HDAC6), a therapeutic target of interest for neurodegenerative diseases, acts at a nexus modulating both proteostasis and intracellular transport. Inhibition of HDAC6 deacetylase activity promotes autophagic clearance of protein aggregates and increases α-tubulin acetylation, thereby enhancing microtubule resiliency and motor protein-microtubule binding, which facilitates intracellular transport and, subsequently, proteostasis. Despite these benefits, advancement of HDAC6 inhibitor therapeutics for neurodegenerative disease has been hindered by inadequate selectivity and CNS-penetrance of first-generation compounds. Here, we characterize a next-generation small molecule HDAC6 inhibitor, EKZ-438, in preclinical models of amyotrophic lateral sclerosis and frontotemporal dementia. We present the pharmacological properties of EKZ-438, which demonstrate high selectivity for HDAC6 (>8500-fold selectivity for HDAC6 versus all other HDAC6 paralogues), low nanomolar potency (12 nM) for HDAC6, and importantly, CNS-penetrance (unbound brain-to-plasma partition coefficient [Kp,uu,brain] ≥ 0.55) and high oral bioavailability (fraction of dose absorbed [F%] = 70). In complementary preclinical in vitro and in vivo immunolabelling and live imaging studies we tested the hypothesis that selective inhibition of HDAC6 deacetylase activity is sufficient to improve pathophysiological proteostasis and intracellular transport deficits in animal models of familial and sporadic amyotrophic lateral sclerosis and frontotemporal dementia. Notably, we extended these findings to human induced pluripotent stem cell-derived neuronal cellular models, supporting the relevance of our findings to human disease. EKZ-438 treatment rescued superoxide dismutase 1 (SOD1) (q < 0.0001) and transactive response DNA binding protein 43 kDa (TDP-43) (q < 0.001) proteostasis defects following an excitotoxic glutamate challenge, and increased survival of SOD1G93A and wild-type motor neurons by 59% (q < 0.0001) and 37% (q < 0.01), respectively, demonstrating in vitro neuroprotection. In SOD1G93A mice, EKZ-438 improved axonal transport by 16% (q < 0.05), motor performance by ∼40% (q < 0.05) and decreased plasma neurofilament light chain levels by 35% (q < 0.05), demonstrating in vivo neuroprotection. In a TDP-43 mouse model, EKZ-438 reduced TDP-43 pathology by ∼30% (q < 0.05) and neuroinflammation by ∼26% (q < 0.05) in the brain, supporting HDAC6 inhibition for sporadic amyotrophic lateral sclerosis and frontotemporal dementia. Furthermore, EKZ-438 treatment improved intracellular transport by 39% (q < 0.001), rescued cytoplasmic TDP-43 accumulation by 87% (q < 0.0001) and restored nuclear TDP-43 splicing activity (P < 0.05) in human TARDBP neurons. These mechanistic improvements aligned with nearly complete rescue of human TARDBP and C9orf72 mutant neuron survival (P < 0.0001). We conclude that selective HDAC6 inhibition represents a promising therapeutic approach for potential disease modification in amyotrophic lateral sclerosis and frontotemporal dementia.

Mammalian oocyte meiosis holds distinct features from mitosis in many aspects. For example, the organisation of the spindle poles, the separation processes of the chromosomes, the way microtubules (MTs) are nucleated and so forth.1 Many issues about oocyte meiosis are still to be addressed. Moreover, in the past decade, researchers found that oocyte meiosis in primates, including humans, employed some specific proteins or structures, making the mechanical study of mammalian oocyte meiosis more complicated.2-4 Among these primate-specific proteins, TUBB8 is the most conspicuous since the Tubb8 mutation in humans accounts for about 30% or more of abnormal clinical cases in MI arrest, fertilisation failure, and early embryo development arrest.5, 6 However, there are still many unaddressed questions about TUBB8. For example, what's the exact mechanism by which TUBB8 function to organise and stabilise spindle MTs? Are there effective and easy strategies to rescue all sorts of spindle defects caused by different TUBB8 mutations? Recently, a work by Hui Luo et al has made significant progress on both questions.7 For the first question, through a combination of multiple cell biological & molecular biology, and biochemistry techniques, they found that TUBB8-D417N expression significantly disrupted its interaction with EB1, a fundamental MT nucleator and polymerizer, and thereby dis-localised EB1; meanwhile, the EB1 protein level didn't change, suggesting that TUBB8 help the correct localisation of EB1. EB1 mislocalisation in turn seriously disrupted the distribution of several other MT nucleators, including CKAP5 and TACC, but didn't affect their protein levels (Figure 1). In addition, TUBB8-D417N expression also broke up the localisation of several critical MT polymerisers and stabilisers, including TPX2, Ran-GTP and KIF11. All these suggest that TUBB8 is fundamentally important for MT nucleation & polymerisation and the maintenance of spindle bipolarity. The author showed that TUBB8-D417N didn't affect the assembly of α/β-tubulin heterodimer, suggesting that TUBB8 is not a MT lattice component but acts like a chaperone. The peculiarity of this chaperone is that it is highly similar to α/β-tubulin. Maybe it is this high similarity that makes TUBB8, as a chaperone, have a high binding affinity to plenty of MAPs (MT-associated proteins) such as EB1, CKAP5, TACC, TPX2, Ran-GTP and KIF11. TUBB8 is not a natural component of mouse oocytes; however, TUBB8-D417N disrupt EB1 localisation presumably through a dominant-negative effect. Thus, under natural conditions, which tubulin isotype acts like TUBB8 in mouse oocytes? The author claimed that TUBB8 directly binds and locates EB1, while EB1 positions CKAP5 and TACC. How about the relationship between TUBB8 and TPX2, Ran-GTP, and KIF11? TUBB8 maintains the correct localisation of these three proteins through direct binding or through EB1? In human oocytes, are there other TUBB isotypes behaving like chaperones but somewhat distinct from TUBB8? The author showed that HDAC8 is not involved in the MT deacetylation caused by TUBB8-D417N; however, there are plenty of other deacetylases, and some (such as HDAC2, SIRT2, etc.) have been reported to regulate tubulin acetylation level. Thus, it would be nice to perform a thorough screen of all deacetylases under TUBB8-D417N expression. Oocytes are transcriptionally silent, and the author showed that TUBB8-D417N didn't affect the protein level of various MAPs above. So how does TUBB8-D417N expression upregulate HDAC6? One simple explanation is that a mouse TUBB8 ortholog stabilises a translational inhibitor of HDAC6, TUBB8-D417N disrupts this stabilisation and inactivates the inhibitor. The author has done proteomics between control oocytes and TUBB8-D417N-treated oocytes, focusing on the change of the translational regulator might provide an answer. Tubulin are stabilised by several other PTMs such as polyglutamylation and tyrosination, in addition to acetylation. The author has found that various tubulin PTMs (malonylation, succinylation, benzoylation, glutarylation, propionylation, lactylation and crotonylation) had significant changes upon TUBB8-D417N expression. Does this indicate that TUBB8 regulate the translation of plenty of PTM-modifying enzymes? Would a combination of inhibitors against several de-acylating enzymes be better for spindle recovery? Nonetheless, it's this study that incites the upper issues, and many others. Therefore, it is a very important and enlightening work. It would be exciting to expect further related investigations. Figure 1 Zhi-Xia Yang wrote the manuscript and made the graphic abstract image. Dong Zhang and Zi-Fu Wang proofread and gave advice. All authors read and approved the final manuscript. We thank the advice and suggestions from our lab members. This work was financially supported by the National Key Research and Development Program of China to Dong Zhang (Grant Nos: 2022YFC2702202 and 2023YFA1800303). The authors declare no conflict of interest. Not applicable.

Rotenone, a lipophilic pesticide, is strongly linked to dopaminergic neuronal loss, primarily through the inhibition of mitochondrial complex I. Beyond its well-characterized neurotoxic effects, rotenone also triggers G2/M arrest in cells, but the molecular mechanisms linking this cell cycle perturbation to neurodegeneration remain unclear. Here, we identify HMGB1 as a key player in this process. HMGB1, known for its roles in genomic integrity and inflammation, exits the nucleus during rotenone-induced G2/M arrest, whereas its nuclear retention protects against mitotic DNA damage and subsequent cell cycle arrest. We found that rotenone-induced tubulin hyperacetylation precedes HMGB1 nuclear exit and is associated with increased mitochondrial ROS (mtROS) levels. Notably, reducing the levels of αTAT1 (alpha-tubulin acetyltransferase 1) lowers mtROS production, thereby preventing HMGB1 nuclear exit and subsequent rotenone-induced G2/M arrest. Although ROS is known to enhance tubulin acetylation, our findings reveal a bidirectional relationship in which tubulin acetylation regulates mtROS production and exacerbates cellular oxidative stress. Moreover, the PARP1 inhibitor PJ34 suppresses HMGB1 nuclear exit and rescues G2/M arrest, suggesting that mtROS-induced DNA damage elevates PARP1 activity, driving HMGB1 PARylation and subsequent translocation, thus impairing DNA damage repair. Together, our findings uncover a previously unknown tubulin acetylation/mtROS/HMGB1 axis as a key driver of rotenone-induced G2/M arrest, highlighting the essential role of nuclear HMGB1 in maintaining genomic stability. Given that dopaminergic neurons in post-mortem PD brains exhibit G2/M arrest suggestive of abortive cell cycle re-entry, targeting this dysregulated axis may offer a promising strategy to mitigate rotenone-induced neurotoxicity.

The detrimental effects of polystyrene nanoplastics (NPs) on human skeletal muscle cells and underlying mechanisms remain largely unclear. Here we exposed mice to NPs and observed significant NP uptake and damages in muscles. RNA sequencing result revealed that many cytoskeleton-related factors were markedly altered by NPs. With cultured human muscle cells, we demonstrate that internalized NPs profoundly changed the microtubule network by causing increased tubulin acetylation, enhanced stabilization, and reduced dynamics. These microtubule changes were accompanied by impaired microtubule-organizing center (MTOC) functionality, defective mechanotransduction capacity linked to YAP deactivation, and critically, compromised function as trafficking tracks for intracellular organelles like mitochondria and lysosomes, leading to accumulation of damaged mitochondria and dysfunctional mitophagy at MTOC location. mtDNA leakage from damaged mitochondria then led to cGAS-Sting activation and accelerated cellular senescence. Mechanistically, NP-induced microtubule hyper-stabilization was driven by deactivation of tubulin deacetylases Sirt2 and HDAC6, leading to α-tubulin hyperacetylation. Further, Sirt2 reactivation/overexpression in muscle cells effectively reduced NP-induced α-tubulin acetylation, mitochondrial damage, cGAS-Sting activation and cellular senescence, as well as the level of cytoplasmic NPs. Our findings unveil a novel mechanism by which NPs promote cellular senescence, highlighting microtubule dynamics as a key mediator of NP-induced damage and a promising therapeutic target.