Regulation of nuclear import of LIM-Kinase 2 in endothelial cells

The activation of the endothelium with various stimuli such as thrombin leads to cell shape change, migration, and proliferation that involve dynamic changes of the actin cytoskeleton. The Rho family GTPases activate Rho-kinase and PAK, which stimulate LIM-kinases. LIM-kinases regulate the actin cytoskeleton through phosphorylation of cofilin. Only very few studies reported about other functions of LIM-kinases, such as its possible role in cell cycle regulation. The function of the LIM-kinases is unknown in endothelial cells. In this study, we answered the following questions: 1. Which LIM-kinase(s) are expressed in endothelial cells? What is the role of LIM-kinases and cofilin phosphorylation in thrombin-induced stress fiber formation and contraction of endothelial cells? How is the LIMK/cofilin pathway regulated in endothelial cells? 2. Does LIMK2 shuttle between the cytosol and the nucleus in endothelial cells? If yes, which are the responsible nuclear localization signals (NLSs) and nuclear export signals (NESs)? How is the nucleocytoplasmic shuttling of LIMK2 regulated in endothelial cells?