Changes in cell shape, cytoskeletal proteins and adhesion sites of cultured cells after extracellular Ca2+ chelation

Brazilian Journal of Medical and Biological Research

C.s. Mermelstein¹  M.i.l. Rebello¹  L.m. Amaral¹  M.l. Costa¹ 

[1] ,Universidade Federal do Rio de Janeiro Instituto de Ciências Biomédicas Departamento de Histologia e EmbriologiaRio de Janeiro RJ ,Brasil

关键词: Cytoskeleton;    Extracellular Ca2+;    Cell shape;    Microfilaments;    Microtubules;    Integrin;   

DOI  :  10.1590/S0100-879X2003000800018

来源: SciELO

【 摘 要 】

Although much is known about the molecules involved in extracellular Ca2+ regulation, the relationship of the ion with overall cell morphology is not understood. The objective of the present study was to determine the effect of the Ca2+ chelator EGTA on the major cytoskeleton components, at integrin-containing adhesion sites, and their consequences on cell shape. Control mouse cell line C2C12 has a well-spread morphology with long stress fibers running in many different directions, as detected by fluorescence microscopy using rhodamine-phalloidin. In contrast, cells treated with EGTA (1.75 mM in culture medium) for 24 h became bipolar and showed less stress fibers running in one major direction. The adhesion plaque protein alpha5-integrin was detected by immunofluorescence microscopy at fibrillar adhesion sites in both control and treated cells, whereas a dense labeling was seen only inside treated cells. Microtubules shifted from a radial arrangement in control cells to a longitudinal distribution in EGTA-treated cells, as analyzed by immunofluorescence microscopy. Desmin intermediate filaments were detected by immunofluorescence microscopy in a fragmented network dispersed within the entire cytoplasm in EGTA-treated cells, whereas a dense network was seen in the whole cytoplasm of control cells. The present results suggest that the role of extracellular Ca2+ in the regulation of C2C12 cell shape can be mediated by actin-containing stress fibers and microtubules and by intermediate filament reorganization, which may involve integrin adhesion sites.

【 授权许可】

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