PKD1/PKCl promotes avb3 integrin recycling and delivery to nascent focal adhesions

To identify kinases that regulate integrin recycling, we have immunoprecipitated avb3 integrin from NIH 3T3 fibroblasts in the presence and absence of primaquine (a drug that inhibits receptor recycling and leads to accumulation of integrins in endosomes) and screened for co-precipitating kinases. Primaquine strongly promoted association of avb3 integrin with PKD1, and fluorescence microscopy indicated that integrin and PKD1 associate at a vesicular compartment that is downstream of a Rab4dependent transport step. PKD1 association was mediated by the C-terminal region of the b3 integrin cytodomain, and mutants of b3 that were unable to recruit PKD1 did not recycle in a PDGF-dependent fashion. Furthermore, suppression of endogenous PKD1 levels by RNAi, or overexpression of catalytically inactive PKD1 inhibited PDGFdependent recycling of avb3 from early endosomes to the plasma membrane and blocked recruitment of avb3 to newly formed focal adhesions during cell spreading. These data indicate that PKD1 influences cell migration by directing vesicular transport of the avb3 integrin heterodimer. The EMBO Journal (2004) 23, 2531–2543. doi:10.1038/ sj.emboj.7600267; Published online 10 June 2004 Subject Categories: membranes & transport; cell & tissue architecture