Cytoskeleton (Hoboken, N.J.)最新文献

{"title":"Fixation Induces Mislocalization of Thin Filament Components in Caenorhabditis elegans Striated Muscle.","authors":"Michael J Kimmich, Pu Zhang, Bob Goldstein, David Pruyne","doi":"10.1002/cm.70194","DOIUrl":"https://doi.org/10.1002/cm.70194","url":null,"abstract":"<p><p>The simple nematode Caenorhabditis elegans has long served as a powerful genetic model system for studying muscle structure and function, with sarcomeres of the striated body wall muscle (BWM) that are considered largely homologous to those in vertebrates. However, we have observed a population of F-actin in BWM separate from I-bands and centered at the sarcomere M-line, something not seen in vertebrate sarcomeres. Here, we investigate whether M-line-associated F-actin is a true feature of worm muscle, or an artifact of sample preparation. Using thin filament components tagged with fluorescent proteins, we confirm that living C. elegans BWM has a traditional sarcomere organization with actin restricted to I-bands, whereas two methods of fixation resulted in varying degrees of mislocalization of actin as well as barbed end capping protein/CapZ and tropomodulin. Additionally, we observe in live animals that α-actinin-rich dense bodies are flanked by discrete patches of CapZ, something we cannot observe in fixed animals, but which provides some support for a model in which dense bodies anchor thin filaments in a manner similar to vertebrate Z-discs. Overall, our work highlights the susceptibility of thin filaments in worm BWM to fixation artifacts and the potential utility in studying sarcomere structure in live animals.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":"e70194"},"PeriodicalIF":1.6,"publicationDate":"2026-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148852050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Author Profile.","authors":"Marcus Winogradzki, Jitesh Pratap","doi":"10.1002/cm.70189","DOIUrl":"https://doi.org/10.1002/cm.70189","url":null,"abstract":"","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":"e70189"},"PeriodicalIF":1.6,"publicationDate":"2026-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148842013","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Captivated by Kinesin.","authors":"Ronald D Vale","doi":"10.1002/cm.70190","DOIUrl":"https://doi.org/10.1002/cm.70190","url":null,"abstract":"<p><p>Few proteins have inspired as much curiosity as kinesin. Since its discovery 40 years ago, kinesin has become one of the best understood molecular machines in biology, yet it continues to reveal new questions about how cells organize and move their contents. Its study transformed not only our understanding of intracellular transport but also the way biochemical mechanisms can be investigated through microscopy. In this essay, I reflect on how I first encountered kinesin and how it taught me to watch cells and proteins directly, letting observation reveal nature's workings.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148815173","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magnesium Cations Modulate Actin Bundles Formed by α-Actinin.","authors":"Jinho Park, Ramsha Hashmi, Eunyoung Moon, Jung Han Kim, Ellen H Kang","doi":"10.1002/cm.70188","DOIUrl":"https://doi.org/10.1002/cm.70188","url":null,"abstract":"<p><p>α-Actinin is an actin-crosslinking protein that influences cytoskeletal organization by forming actin bundles or networks. Divalent cations, such as magnesium cations (Mg²⁺), promote bundling through counterion condensation. While α-actinin and Mg²⁺ individually promote actin bundle assembly, their combined effects on actin bundling remain unclear. Here, we determine how Mg²⁺ affects α-actinin's binding to filaments and its subsequent bundling activities through biophysical analysis. We show that increasing Mg²⁺ concentrations enhance the binding of α-actinin to actin filaments, producing more compact bundles instead of loose networks. Molecular dynamics simulation indicates that Mg²⁺ modulates the interaction between filaments and the calponin homology 1 domain of α-actinin. We propose a mechanism by which divalent cations and α-actinin crosslinking act simultaneously to drive actin bundle formation.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":"e70188"},"PeriodicalIF":1.6,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148809260","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Author Profile: Ilgin Isiltan.","authors":"Ilgin Isiltan","doi":"10.1002/cm.70186","DOIUrl":"https://doi.org/10.1002/cm.70186","url":null,"abstract":"","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":"e70186"},"PeriodicalIF":1.6,"publicationDate":"2026-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148809145","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assembly and Maintenance of Myofibrils in the Heart.","authors":"Elisabeth Ehler","doi":"10.1002/cm.70187","DOIUrl":"https://doi.org/10.1002/cm.70187","url":null,"abstract":"<p><p>The assembly of actin and myosin to the paracrystalline arrangement of myofibrils in striated muscle, that is, heart and skeletal, has puzzled many a cell biologist. Different models, based on cultured cardiomyocytes, were proposed for the last 30 years to explain the sequence of events. These were then evaluated during heart development in embryos in situ and more recently in cardiomyocytes that were derived from human induced pluripotent stem cells (iPSC-CMs). A lot of the initial work was quite descriptive but recent advances in gene editing technology and in super resolution microscopy allow a more targeted functional analysis and will give unprecedented insight. This review will discuss the general principles of myofibril assembly in the heart and cover new findings on myofibril maintenance and turnover.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":"e70187"},"PeriodicalIF":1.6,"publicationDate":"2026-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148802257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Transcripts and Protein Expression of Different HMW Non-Myofibrillar Tpm1 Isoforms in Human iPSC-CMs During Differentiation.","authors":"Dipak K Dube, Syamalima Dube, Patricia Benz, Jushuo Wang, Samender Randhawa, Yingli Fan, Zhen Ma, Xinrui Wang, Shiyang Sun, Joseph W Sanger, Jean M Sanger, Bernard J Poiesz","doi":"10.1002/cm.70185","DOIUrl":"https://doi.org/10.1002/cm.70185","url":null,"abstract":"&lt;p&gt;&lt;p&gt;Mammals have four tropomyosin (TPM) genes (TPM1, TPM2, TPM3, and TPM4) that produce various isoforms through alternative splicing. TPM1 generates both myofibrillar (Tpm1.1, Tpm1.2) and non-myofibrillar isoforms, including those with an exon 9d peptide or with an exon 9a peptide. These non-myofibrillar isoforms are involved in regulating actin-based structures and processes in non-muscle cells. This study focused on the expression of the non-myofibrillar HMW Tpm1 isoforms (Tpm1.3, Tpm1.4, Tpm1.5, Tpm1.6, Tpm1.7, and Tpm1.14) during human inducible pluripotent stem cells (hiPSC) differentiation into cardiomyocytes (CMs) at different time points (Days 0, 5, 10, 15, 20). We have determined the expression of various Tpm1 transcripts by qRT-PCR using isoform-specific primer-pairs. Western blotting with Tpm1-exon 6a and Tpm1-exon 9d antibodies and 2D Western blotting with Tpm1-exon 6a antibody followed by mass spectra analyses were used to evaluate protein expression. Transcripts of non-myofibrillar Tpm1 isoforms peaked at Day 15 and continued at a slightly lower level in mature hiPSC-CM until Day 20. However, no expression of Tpm1.3 or Tpm1.14 has been observed. Protein expression of Tpm1.4, Tpm1.5, Tpm1.6, and Tpm1.7 increases up to Day 15 but practically disappears by Day 20 hiPSC-CM, suggesting their production is decreased, or more likely they are degraded intracellularly. The results suggest that the proteins have the potential to be transiently involved in the early stages of CM differentiation. This study also demonstrates that Tpm1.5, when fused with YFP in an expression construct and transfected into embryonic chicken CM and Day 20 mature hiPSC-CMs, can be organized into cardiac myofibrils despite being previously characterized as a non-muscle isoform. Our observation is further substantiated by the fact that YFP-Tpm1.5 fusion protein can be ectopically expressed and incorporated into the myofibrils of chicken myotube skeletal muscle, which is known to be more stringent than cardiac muscle with regards to myofibril remodeling. Paradoxically, anti-6a antibody fails to recognize the organized YFP-Tpm1.5 fusion protein in embryonic chicken CMs, embryonic chicken skeletal muscle myotubes, or in Day 20 mature hiPSC-CMs. Interestingly, the antibody recognizes the denatured YFP-Tpm1 fusion protein in Western blot analyses. It is well-documented in the literature that an antibody epitope may fail to recognize its antigen when the antigen is in its native state in living cells, often because the epitope is buried, altered conformationally, or inaccessible. Conversely, while the Tpm1.Ex6a antibody stains Tpm1.5 in cell nuclei, the YFP-Tpm1.5 fusion protein does not localize to the cell nuclei. This suggests conformational differences between nuclear and cytoplasmic Tpm1 protein(s) and differential access of the fusion protein to different cellular locations. This also suggests that it is endogenous Tpm1 6a-containing protein identified in the nucl","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":"e70185"},"PeriodicalIF":1.6,"publicationDate":"2026-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148714611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Labeling Strategies for Monitoring Cytoskeleton Dynamics in Cultured Epithelial Cells.","authors":"Victoria Levario-Diaz, Lakshmi Nyapathi-Gopinath, Jonah Luka Voigt, Katharina Weber, Marlene Maager, Veselin Nasufovic, Elisabetta Ada Cavalcanti-Adam","doi":"10.1002/cm.70173","DOIUrl":"https://doi.org/10.1002/cm.70173","url":null,"abstract":"<p><p>Collective cell migration relies on coordinated cytoskeletal remodeling, yet the impact of live-cell actin filament probes on these dynamics remains poorly characterized. Here, we systematically compared the performance and cellular effects of fluorogenic jasplakinolide-based probes, SiR-actin and SiR-XActin, with the genetically encoded Lifeact reporter in epithelial monolayers. Using an injury-free wound healing assay combined with widefield images, particle image velocimetry, kymographs, and FUCCI-based cell cycle tracking system, we assessed how probe choice, efflux inhibition, and genetic modification influence actin organization, migration, and proliferation. SiR-XActin provided robust labeling of actin filaments with minimal perturbation in migration rate, directionality, or cell cycle progression, enabling stable visualization of cytoskeletal dynamics in monolayers. In contrast, SiR-actin and Lifeact produced either probe- or cell line-specific effects on migration persistence and wound closure, particularly under prolonged imaging. The use of verapamil, a commonly used phenylalkylamine-derived calcium channel blocker, improved probe retention and migratory persistence without altering proliferation. In contrast, FUCCI-expressing monolayers showed impaired motility independent of probe type, potentially reflecting cytoskeletal constraints associated with cell-cycle reporters. Lifeact-expressing cells exhibited an initial increase in migration rate followed by an incomplete wound closure, consistent with mild actin stabilization. Together, these findings identify SiR-XActin as a minimally perturbative, high-fidelity probe for monitoring actin filament dynamics during collective epithelial migration and highlight the importance of evaluating probe-cell compatibility for live cytoskeletal studies.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":1.6,"publicationDate":"2026-08-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148708676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determining Proximities of Sarcomeric Proteins in Living Skeletal Muscle Cells Using FRET Imaging.","authors":"Jushuo Wang, Yingli Fan, Vasundhara Muthu, Symalima Dube, Naruki Sato, Dipak K Dube, Jean M Sanger, Joseph W Sanger","doi":"10.1002/cm.70169","DOIUrl":"https://doi.org/10.1002/cm.70169","url":null,"abstract":"<p><p>The technique of fluorescence resonance energy transfer (FRET) has been used in this study to determine the proximities (efficiencies, i.e., E%) of interacting proteins in sarcomeres in living cultured embryonic chicken skeletal muscle cells to draw up a FRETsome of a sarcomere in mature myofibrils. During this study, two known Z-band proteins, FATZ (also called myozenin), and telethonin, were found to be actin binding proteins. The Efficiency of the F-actin and telethonin pair was measured to be 15%, while the F-actin and FATZ pair was 18%. The known F-actin and alpha-actinin interactions resulted in an efficiency of 13%. The new actin binding properties of FATZ and telethonin were confirmed by F-actin pull down experiments. By placing a donor probe (CeFP) on one end of the FATZ molecule and the acceptor probe (YFP) on the other end of FATZ, we were able to determine that the two termini moved apart from each other as the dense bodies of the nascent myofibrils fused with one another to form the Z-bands of mature myofibrils. Three other proteins of the dense bodies, i.e., myotilin, alpha-actinin and ArgBP2 also underwent similar termini separation changes as the dense bodies transformed into Z-bands of mature myofibrils. The highest efficiencies were measured for MyBP-C interactions with myosin heavy chains (35%), myosin light chains (35%), and F-actin (31%). The establishment of a sarcomere FRETsome of these interactions in control sarcomeres in mature myofibrils in living transfected skeletal muscles establishes a foundation on which the introduction of individual mutated sarcomeric proteins involved in different muscle diseases will have on their interactions with control partner sarcomeric proteins in mature myofibrils.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":"e70169"},"PeriodicalIF":1.6,"publicationDate":"2026-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148671392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cytoskeleton-Membrane Uncoupling in Duchenne Muscular Dystrophy: Implications for Newborn Screening and Early Protection.","authors":"Houda Cohen, Nora Hosny, Brian R Thompson, Joseph M Metzger","doi":"10.1002/cm.70175","DOIUrl":"https://doi.org/10.1002/cm.70175","url":null,"abstract":"<p><p>The cytoskeleton of striated muscle integrates force transmission, mechanotransduction, and sarcolemmal stability through coordinated networks of sarcomeres, costameres, and intermediate filaments. Together, these systems establish mechanical continuity between the contractile apparatus, the sarcolemma, and the extracellular matrix. In Duchenne muscular dystrophy (DMD), loss of dystrophin disrupts cytoskeleton-membrane coupling, resulting in early mechanical instability, abnormal calcium influx, and progressive myofiber injury. Although the genetic defect is present from birth, clinical diagnosis is typically made only after substantial tissue remodeling has already occurred, highlighting a critical gap between disease onset and clinical recognition. Newborn screening now enables detection during a pre-symptomatic phase in which muscle architecture remains relatively preserved, reframing DMD as a disorder initiated by early mechanical instability within a dynamically developing tissue environment. Current therapeutic strategies, including corticosteroids, exon-skipping approaches, gene replacement therapies, and epigenetic modulation, primarily target established pathology rather than early disease mechanisms. In contrast, earlier intervention may offer the opportunity to preserve cytoskeletal integrity and stabilize the sarcolemma, thereby limiting downstream degenerative cascades. Together, these considerations support a revised framework in which cytoskeleton-membrane uncoupling represents an early and potentially actionable event in DMD pathogenesis.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":"e70175"},"PeriodicalIF":1.6,"publicationDate":"2026-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148622821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}