GRASP depletion–mediated Golgi destruction decreases cell adhesion and migration via the reduction of a5ß1 integrin

Ahat, Erpan; Xiang, Yi; Zhang, Xiaoyan; Bekier, Michael E.; Wang, Yanzhuang

Using GRASP-knockdown and GRASP-KO cells, we demonstrated that disrupting the Golgi stacks reduced cell adhesion and migration. As integrins are key proteins in these cellular activities, we determined the protein level of nine integrins that are known to be expressed in HeLa cells. Among these integrin subunits, α5 and β1, the major and best-characterized integrins in HeLa cells, exhibited the most dramatic reduction in GRASP-KO cells, while other integrins did not change or only modestly decreased. This demonstrates that different integrins are regulated differently in their expression, as previously described (Judware and Culp, 1997; Palomino et al., 2005) . We then used two different antibodies and different gel systems to further characterize α5β1 integrin in GRASP-KO cells. We found that both mature integrins and the individual components in the complex were all reduced by GRASP depletion. More importantly, restoration of the α5β1-integrin level in GRASP-KO cells rescued the reduced cell adhesion and migration phenotype. These results indicate that the reduced cell adhesion and migration after GRASP depletion is mostly attributable to the reduced α5β1-integrin expression.