Calmodulin bound to stress fibers but not microtubules involves regulation of cell morphology and motility.
Calmodulin (CaM) is a major cytoplasmic calcium receptor that performs multiple functions including cell motility. To investigate the mechanism of the regulation of CaM on cell morphology and motility, first we checked the distribution of CaM in the living cells using GFP-CaM as an indicator. We found that GFP-CaM showed a fiber-like distribution pattern in the cytosol of living Potorous tridactylis kidney (PtK2) cells but not in living HeLa cells. The endogenous CaM in heavily permeabilized HeLa was also found to display a fiber-like distribution pattern. Further examination showed that the distribution pattern of GFP-CaM was same as that of stress fibers, but not microtubules. Co-immunoprecipitation also showed that CaM can interact with actin directly or indirectly. The microinjection of trp peptide, a specific inhibitor of CaM, attenuated the polymerization of stress fibers and induced the alteration of cell morphology. A wound-healing assay and a single cell tracking experiment showed that CaM in PtK2 cells could increase cell motility. The data we have got from living cells suggested that CaM affect cell morphology and motility through binding to stress fibers and regulate f-actin polymerization.
Yuan
Jun
J
Jiangsu Key Laboratory for Molecular and Medical Biotechnology, Nanjing Normal University, #1 Wen Yuan Road, Nanjing, China.
Shi
Guo-Xin
GX
Shao
Yue
Y
Dai
Gu
G
Wei
Jun-Ning
JN
Chang
Donald C
DC
Li
Chao-Jun
CJ
D000818:Animals; D002147:Calmodulin / Q000235:genetics / Q000378:metabolism* / Q000502:physiology*; D002465:Cell Movement / Q000502:physiology*; D048430:Cell Shape / Q000502:physiology*; D002478:Cells, Cultured; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007668:Kidney / Q000166:cytology; D008870:Microtubules / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000502:physiology; D048328:Potoroidae; D011485:Protein Binding; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D022502:Stress Fibers / Q000378:metabolism*; D014018:Tissue Distribution; D014162:Transfection
D002147:Calmodulin; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D009219:Myosin-Light-Chain Kinase