PKD1/PKC┬Á promotes alphavbeta3 integrin recycling and delivery to nascent focal adhesions

Authors:
Woods AJ, White DP, Caswell PT and Norman JC
In:
Source: EMBO J
Publication Date: (2004)
Issue: 23(13): 2531-2543
Research Area:
Dermatology/Tissue Engineering
Cells used in publication:
Embryonic fibroblast, mouse (MEF) immort
Species: mouse
Tissue Origin: embryo
Platform:
Nucleofector® I/II/2b
Experiment
Knockdown of PDK1 with an siRNA expression plasmid in the mouse fibroblast cell line NIH 3T3 inhibited alphavbeta3 integrin delivery and recycling to the plasma membrane, reduced migration of cells in a wound healing assay, and altered the distribution of alphavbeta3 integrin in migrating cells.
Abstract
To identify kinases that regulate integrin recycling, we have immunoprecipitated alphavbeta3 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 alphavbeta3 integrin with PKD1, and fluorescence microscopy indicated that integrin and PKD1 associate at a vesicular compartment that is downstream of a Rab4-dependent transport step. PKD1 association was mediated by the C-terminal region of the beta3 integrin cytodomain, and mutants of beta3 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 PDGF-dependent recycling of alphavbeta3 from early endosomes to the plasma membrane and blocked recruitment of alphavbeta3 to newly formed focal adhesions during cell spreading. These data indicate that PKD1 influences cell migration by directing vesicular transport of the alphavbeta3 integrin heterodimer.