Alpha4 integrins are type I cAMP-dependent protein kinase-anchoring proteins.
A-kinase anchoring proteins (AKAPs) control the localization and substrate specificity of cAMP-dependent protein kinase (PKA), tetramers of regulatory (PKA-R) and catalytic (PKA-C) subunits, by binding to PKA-R subunits. Most mammalian AKAPs bind Type II PKA through PKA-RII (ref. 2), whereas dual specificity AKAPs bind both PKA-RI and PKA-RII (ref. 3). Inhibition of PKA-AKAP interactions modulates PKA signalling. Localized PKA activation in pseudopodia of migrating cells phosphorylates alpha4 integrins to provide spatial cues governing cell motility. Here, we report that the alpha4 cytoplasmic domain is a Type I PKA-specific AKAP that is distinct from canonical AKAPs in two ways: the alpha4 interaction requires the PKA holoenzyme, and is insensitive to amphipathic peptides that disrupt most PKA-AKAP interactions. We exploited type-specific PKA anchoring peptides to create genetically encoded baits that sequester specific PKA isoforms to the mitochondria and found that mislocalization of Type I, but not Type II, PKA disrupts alpha4 phosphorylation and markedly inhibits the velocity and directional persistence of cell migration.
Lim
Chinten James
CJ
Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA.
Han
Jaewon
J
Yousefi
Nima
N
Ma
Yuliang
Y
Amieux
Paul S
PS
McKnight
G Stanley
GS
Taylor
Susan S
SS
Ginsberg
Mark H
MH
D000818:Animals; D015153:Blotting, Western; D016466:CHO Cells; D002465:Cell Movement; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D006224:Cricetinae; D003412:Cricetulus; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism*; D004285:Dogs; D005260:Female; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D039441:Integrin alpha4 / Q000235:genetics / Q000378:metabolism*; D039041:Integrin alpha4beta1 / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008856:Microscopy, Fluorescence; D010766:Phosphorylation; D011485:Protein Binding; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
D039041:Integrin alpha4beta1; D021122:Protein Subunits; D011993:Recombinant Fusion Proteins; D039441:Integrin alpha4; D049452:Green Fluorescent Proteins; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases