Szabo Eva, Papp Sylvia, Opas Michal
Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.
J Cell Physiol. 2007 Oct;213(1):269-77. doi: 10.1002/jcp.21122.
Calreticulin is an ER calcium-storage protein, which influences gene expression and cell adhesion. In this study, we analysed the differences in adhesive properties of calreticulin under- and overexpressing fibroblasts in relation to the calmodulin- and calcium/calmodulin-dependent kinase II (CaMK II)-dependent signalling pathways. Cells stably underexpressing calreticulin had elevated expression of calmodulin, activated CaMK II, activated ERK and activated c-src. Inhibition of calmodulin by W7, and CaMK II by KN-62, caused the otherwise weekly adhesive calreticulin underexpressing cells to behave like the overexpressing cells, via induction of increased cell spreading. Increased vinculin, activated paxillin, activated focal adhesion kinase and fibronectin levels were observed upon inhibition of either the calmodulin or the CaMK II signalling pathways, which was accompanied by an increase in cell spreading and focal contact formation. Both KN-62 and W7 treatment increased cell motility in underexpressing cells, but W7 treatment led to loss of directionality. Thus, both the calmodulin and CaMK II signalling pathways influence cellular spreading and motility, but subtle differences exist in their distal effects on motility effectors.
钙网蛋白是一种内质网钙储存蛋白，它影响基因表达和细胞黏附。在本研究中，我们分析了钙网蛋白低表达和高表达的成纤维细胞在与钙调蛋白及钙/钙调蛋白依赖性激酶II（CaMK II）相关的信号通路中的黏附特性差异。稳定低表达钙网蛋白的细胞中，钙调蛋白表达升高，CaMK II被激活，细胞外调节蛋白激酶（ERK）被激活，c-src也被激活。用W7抑制钙调蛋白，用KN-62抑制CaMK II，可使原本黏附性较弱的低表达钙网蛋白的细胞表现得像高表达细胞，这是通过诱导细胞铺展增加实现的。抑制钙调蛋白或CaMK II信号通路后，可观察到纽蛋白增加、桩蛋白激活、黏着斑激酶激活以及纤连蛋白水平升高，同时伴随着细胞铺展和黏着斑形成增加。KN-62和W7处理均增加了低表达细胞的运动性，但W7处理导致方向性丧失。因此，钙调蛋白和CaMK II信号通路均影响细胞铺展和运动性，但它们对运动效应器的远端效应存在细微差异。
