title: The association of calmodulin with central spindle regulates the initiation of cytokinesis in HeLa cells.
abstract: Calmodulin is a major cytoplasmic calcium receptor that performs multiple functions in the cell including cytokinesis. Central spindle appears between separating chromatin masses after metaphase-anaphase transition. The interaction of microtubules from central spindle with cell cortex regulates the cleavage furrow formation. In this paper, we use green fluorescence protein (GFP)-tagged calmodulin as a living cell probe to examine the detailed dynamic redistribution and co-localization of calmodulin with central spindle during cytokinesis and the function of this distribution pattern in a tripolar HeLa cell model. We found that calmodulin is associated with spindle microtubules during mitosis and begins to aggregate with central spindle after anaphase initiation. The absence of either central spindle or central spindle-distributed calmodulin is correlated with the defect in the formation of cleavage furrow, where contractile ring-distributed CaM is also extinct. Further analysis found that both the assembly of central spindle and the formation of cleavage furrow are affected by the W7 treatment. The microtubule density of central spindle was decreased after the treatment. Only less than 10% of the synchronized cells enter cytokinesis when treated with 25 microM W7, and the completion time of furrow regression is also delayed from 10 min to at least 40 min. It is suggested that calmodulin plays a significant role in cytokinesis including furrow formation and regression, The understanding of the interaction between calmodulin and microtubules may give us insight into the mechanism through which calmodulin regulates cytokinesis.
authors.affiliation: Jiangsu Key Laboratory for Molecular & Medical Biotechnology, School of Life Sciences, Nanjing Normal University, Nanjing 210097, Jiangsu Province, China.
authors.forename: Yue-Yue
authors.initials: YY
authors.lastname: Yu
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Gu
authors.initials: G
authors.lastname: Dai
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Sun
authors.forename: Chuan-Jun
authors.initials: CJ
authors.lastname: Wen
authors.forename: Dong-Hong
authors.initials: DH
authors.lastname: Zhao
authors.forename: Donald C
authors.initials: DC
authors.lastname: Chang
authors.forename: Chao-Jun
authors.initials: CJ
authors.lastname: Li
mesh_terms: D000705:Anaphase; D002147:Calmodulin / Q000378:metabolism*; D048749:Cytokinesis; D049452:Green Fluorescent Proteins; D006367:HeLa Cells; D006801:Humans; D008870:Microtubules / Q000378:metabolism; D008938:Mitosis; D021381:Protein Transport; D008941:Spindle Apparatus / Q000378:metabolism*; D013449:Sulfonamides / Q000494:pharmacology; D013995:Time
chemical_list: D002147:Calmodulin; D013449:Sulfonamides; D049452:Green Fluorescent Proteins; C017967:W 7