{"title":"Actin Isovariant ACT2-Mediated Cellular Auxin Homeostasis Regulates Lateral Root Organogenesis in Arabidopsis thaliana.","authors":"Aya Hanzawa, Arifa Ahamed Rahman, Abidur Rahman","doi":"10.1002/cm.21956","DOIUrl":"https://doi.org/10.1002/cm.21956","url":null,"abstract":"<p><p>Lateral root (LR) organogenesis is regulated by cellular flux of auxin within pericycle cells, which depends on the membrane distribution and polar localization of auxin carrier proteins. The correct distribution of auxin carrier proteins relies on the intracellular trafficking of these proteins aided by filamentous actin as a track. However, the precise role of actin in lateral root development is still elusive. Here, using vegetative class actin isovariant mutants, we revealed that loss of actin isovariant ACT8 led to increased lateral root formation. The distribution of auxin within pericycle cells was altered in act8 mutant, primarily due to the altered distribution of AUX1 and PIN7. Interestingly, incorporation of act2 mutant in act8 background (act2act8) effectively nullified the LR phenotype observed in act8 mutant, indicating that ACT2 plays an important role in LR development. To explore further, we investigated the possibility that the act8 mutant's LR phenotype and cellular auxin distribution resulted from ACT2 overexpression. Consistent with the idea, enhanced lateral root formation, altered AUX1, PIN7 expression, and auxin distribution in pericycle cells were observed in ACT2 overexpression lines. Collectively, these results suggest that actin isovariant ACT2 but not ACT8 plays a pivotal role in regulating source-to-sink auxin distribution during lateral root organogenesis.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142645259","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}
Jushuo Wang, Yingli Fan, Syamalima Dube, Patricia Benz, Dipak Dube, Jean M Sanger, Joseph W Sanger
{"title":"Analyses of Off-Target Effects on Cardiac and Skeletal Muscles by Berberine, a Drug Used to Treat Cancers and Induce Weight Loss.","authors":"Jushuo Wang, Yingli Fan, Syamalima Dube, Patricia Benz, Dipak Dube, Jean M Sanger, Joseph W Sanger","doi":"10.1002/cm.21950","DOIUrl":"https://doi.org/10.1002/cm.21950","url":null,"abstract":"<p><p>Previous reports from our laboratory describing the formation of myofibrils in cultured embryonic cardiac and skeletal muscle cells have proposed that myofibrillogenesis occurs in three steps of increasing protein organization: beginning with premyofibrils, followed by nascent myofibrils, and ending in mature myofibrils. Inhibitors of the ubiquitin proteasome system (UPS) prevented nascent myofibrils from progressing directly to mature myofibrils in cultured cardiac and skeletal muscle cells, supporting a three-step model of assembly in which some of the proteins in nascent myofibrils are proteolyzed to allow the assembly of mature myofibrils. Application of UPS inhibitors on cultured muscle cells suggests possible explanations for the off-target cardiac and skeletal muscle adverse effects of UPS drugs, which are used on cancer patients. Berberine, a plant derivative, has been used to treat various cancers, including multiple myelomas. In contrast to the use of UPS drugs, success was reported with Berberine in multiple myeloma patients with no off-target effects on their hearts. We have exposed cultured cardiac and skeletal muscle cells to Berberine, a ligase inhibitor of UHRF1 (ubiquitin-like with PHD and RING finger domains). Berberine inhibited myofibril assembly at the nascent myofibril stage in embryonic skeletal muscle cells but had no effect in the assembly of mature myofibrils in embryonic heart cells. RT-PCR experiments demonstrated Berberine inhibition of mRNA for muscle myosin II heavy chains but not for muscle actin mRNA in skeletal muscle cells. Berberine is also being used as a popular weight losing compound, because it is much cheaper and available without a prescription than the semaglutide containing weight losing drugs (Wegovy and Ozempic). In contrast to Berberine, semaglutide had no effects on myofibril assembly in culture assays for both cardiac and skeletal muscle cells. We postulate that analyses of cultured embryonic cardiac and skeletal muscle cells will provide a preclinical assay for the testing of novel cancer drugs with improved outcomes for patients, an important goal for cancer therapeutics.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142633794","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":"Alteration of Cytoskeletal Proteins Leads to Retinal Degeneration in Drosophila.","authors":"Surajita Sahu, Monalisa Mishra","doi":"10.1002/cm.21955","DOIUrl":"https://doi.org/10.1002/cm.21955","url":null,"abstract":"<p><p>The eye holds a special fascination for many neuroscientists because of its meticulously organized structure. Vertebrates typically possess a simple camera-type eye, whereas the compound eye structure is predominantly observed in arthropods including model organism Drosophila melanogaster. Cell shape, cell polarization, and tissue integrity are the cell biological processes crucial for shaping the eye, which directly or indirectly depends on the cytoskeleton. Henceforth the cytoskeleton, specifically actin microfilaments, essentially has a dynamic role in the normal development and growth of eye structure. This review provides insight into the roles played by the actin cytoskeleton during the development and maintenance of the Drosophila eye.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142592429","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}
Kyle P Smith, Srinivas Chakravarthy, Amit Rahi, Manas Chakraborty, Kristen M Vosberg, Marco Tonelli, Maximilian G Plach, Arabela A Grigorescu, Joseph E Curtis, Dileep Varma
{"title":"SEC-SAXS/MC Ensemble Structural Studies of the Microtubule Binding Protein Cdt1 Show Monomeric, Folded-Over Conformations.","authors":"Kyle P Smith, Srinivas Chakravarthy, Amit Rahi, Manas Chakraborty, Kristen M Vosberg, Marco Tonelli, Maximilian G Plach, Arabela A Grigorescu, Joseph E Curtis, Dileep Varma","doi":"10.1002/cm.21954","DOIUrl":"10.1002/cm.21954","url":null,"abstract":"<p><p>Cdt1 is a mixed folded protein critical for DNA replication licensing and it also has a \"moonlighting\" role at the kinetochore via direct binding to microtubules and the Ndc80 complex. However, it is unknown how the structure and conformations of Cdt1 could allow it to participate in these multiple, unique sets of protein complexes. While robust methods exist to study entirely folded or unfolded proteins, structure-function studies of combined, mixed folded/disordered proteins remain challenging. In this work, we employ orthogonal biophysical and computational techniques to provide structural characterization of mitosis-competent human Cdt1. Thermal stability analyses shows that both folded winged helix domains1 are unstable. CD and NMR show that the N-terminal and linker regions are intrinsically disordered. DLS shows that Cdt1 is monomeric and polydisperse, while SEC-MALS confirms that it is monomeric at high concentrations, but without any apparent inter-molecular self-association. SEC-SAXS enabled computational modeling of the protein structures. Using the program SASSIE, we performed rigid body Monte Carlo simulations to generate a conformational ensemble of structures. We observe that neither fully extended nor extremely compact Cdt1 conformations are consistent with SAXS. The best-fit models have the N-terminal and linker disordered regions extended into the solution and the two folded domains close to each other in apparent \"folded over\" conformations. We hypothesize the best-fit Cdt1 conformations could be consistent with a function as a scaffold protein that may be sterically blocked without binding partners. Our study also provides a template for combining experimental and computational techniques to study mixed-folded proteins.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142585088","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":"Myosins on the Move: A Special Issue on Myosins and Myosin-Dependent Cell Processes.","authors":"Joanna Moraczewska, Julian Guttman","doi":"10.1002/cm.21953","DOIUrl":"https://doi.org/10.1002/cm.21953","url":null,"abstract":"","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142585085","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}
Saurabh S Kulkarni, Rachel E Stephenson, Sarah Amalraj, Angelo Arrigo, Ewelina Betleja, James J Moresco, John R Yates, Moe R Mahjoub, Ann L Miller, Mustafa K Khokha
{"title":"The Heterotaxy Gene CCDC11 Is Important for Cytokinesis via RhoA Regulation.","authors":"Saurabh S Kulkarni, Rachel E Stephenson, Sarah Amalraj, Angelo Arrigo, Ewelina Betleja, James J Moresco, John R Yates, Moe R Mahjoub, Ann L Miller, Mustafa K Khokha","doi":"10.1002/cm.21952","DOIUrl":"10.1002/cm.21952","url":null,"abstract":"<p><p>Mutations in CCDC11 (cfap53) have been identified in multiple patients with heterotaxy (Htx), a disorder of left-right (LR) patterning of the internal organs. In Xenopus, depletion of Ccdc11 causes defects in LR patterning, recapitulating the patient phenotype. Upon Ccdc11 depletion, monociliated cells of the Left-Right Organizer (LRO) exhibit multiple cilia per cell. Unexpectedly, we found that Ccdc11 is necessary for successful cytokinesis, explaining the multiciliation phenotype observed in Ccdc11-depleted cells. The small GTPase RhoA is critical for cytokinesis, and our Ccdc11 depletion phenotypes are reminiscent of RhoA loss of function. Here, we demonstrate that during cytokinesis CCDC11 is localized to the cytokinetic contractile ring overlapping with RhoA, and CCDC11 regulates total RhoA protein levels. Our results connect CCDC11 to cytokinesis and LR patterning via RhoA regulation, providing a potential mechanism for heterotaxy disease pathogenesis.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142549302","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":"Myosin VI Is Associated With the Endoplasmic Reticulum in Regions of Sertoli Cells Containing Tubulobulbar Complexes.","authors":"Samuel Tretjakov, Prunveer Palia, A Wayne Vogl","doi":"10.1002/cm.21949","DOIUrl":"https://doi.org/10.1002/cm.21949","url":null,"abstract":"<p><p>Myosin VI has been reported by others to localize in association with various regions of apical tubulobulbar complexes (TBCs) at sites of attachment between Sertoli cells and late spermatids in the mouse. Tubulobulbar complexes internalize \"intact\" intercellular junctions during sperm release and during spermatocyte translocation through the blood-testis barrier. Here, we use super-resolution (STED-stimulated emission depletion) and electron microscopy of immunolabeled sections of rat testis to clearly define the localization of anti-myosin VI reactivity both at apical and basal sites in the epithelium. In data stacks collected by STED imaging, staining at TBCs was predominantly associated with bulb regions of the complexes. At apical sites, when data stacks were analyzed with an Imaris software, staining appeared around and extended between adjacent bulbs. At basal sites, in addition to labeling at TBC bulbs, reactive sites appeared concentrated in regions close to but not directly associated with intercellular junctions. At the ultrastructural level, labeling was predominantly associated with cisternae of the endoplasmic reticulum associated with the bulbs of TBCs and near to basal junction complexes. We conclude that myosin VI may be associated with specific subdomains of the endoplasmic reticulum related to TBC bulbs and associated basal junction complexes between Sertoli cells.</p>","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142402191","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":"Remembrance of Robert S. Adelstein: Mr. Nonmuscle Myosin 2.","authors":"James R Sellers","doi":"10.1002/cm.21948","DOIUrl":"https://doi.org/10.1002/cm.21948","url":null,"abstract":"","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142402192","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":"Remembrance of Edward D. Korn: A Pioneer in Our Field.","authors":"John A Hammer","doi":"10.1002/cm.21942","DOIUrl":"10.1002/cm.21942","url":null,"abstract":"","PeriodicalId":72766,"journal":{"name":"Cytoskeleton (Hoboken, N.J.)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142333683","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}