title: Spatial regulation of the cAMP-dependent protein kinase during chemotactic cell migration.
abstract: Historically, the cAMP-dependent protein kinase (PKA) has a paradoxical role in cell motility, having been shown to both facilitate and inhibit actin cytoskeletal dynamics and cell migration. In an effort to understand this dichotomy, we show here that PKA is regulated in subcellular space during cell migration. Immunofluorescence microscopy and biochemical enrichment of pseudopodia showed that type II regulatory subunits of PKA and PKA activity are enriched in protrusive cellular structures formed during chemotaxis. This enrichment correlates with increased phosphorylation of key cytoskeletal substrates for PKA, including the vasodilator-stimulated phosphoprotein (VASP) and the protein tyrosine phosphatase containing a PEST motif. Importantly, inhibition of PKA activity or its ability to interact with A kinase anchoring proteins inhibited the activity of the Rac GTPase within pseudopodia. This effect correlated with both decreased guanine nucleotide exchange factor activity and increased GTPase activating protein activity. Finally, inhibition of PKA anchoring, like inhibition of total PKA activity, inhibited pseudopod formation and chemotactic cell migration. These data demonstrate that spatial regulation of PKA via anchoring is an important facet of normal chemotactic cell movement.
authors.affiliation: Department of Pharmacology and the Vermont Cancer Center, The University of Vermont, 149 Beaumont Avenue, HSRF 322, Burlington, VT 05405-0075, USA. alan.howe@uvm.edu
authors.forename: Alan K
authors.initials: AK
authors.lastname: Howe
authors.forename: Linda C
authors.initials: LC
authors.lastname: Baldor
authors.forename: Brian P
authors.initials: BP
authors.lastname: Hogan
mesh_terms: D000818:Animals; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D002633:Chemotaxis / Q000502:physiology*; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D020690:GTPase-Activating Proteins / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D047468:Immunoprecipitation; D008840:Microfilament Proteins / Q000378:metabolism; D008856:Microscopy, Fluorescence; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism; D011554:Pseudopodia / Q000378:metabolism*; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D000098662:Vasodilator-Stimulated Phosphoprotein
chemical_list: D015815:Cell Adhesion Molecules; D020690:GTPase-Activating Proteins; D020662:Guanine Nucleotide Exchange Factors; D008840:Microfilament Proteins; D010750:Phosphoproteins; D000098662:Vasodilator-Stimulated Phosphoprotein; D054746:Cyclic AMP-Dependent Protein Kinase Type II; D017868:Cyclic AMP-Dependent Protein Kinases; D017027:Protein Tyrosine Phosphatases; D020744:rac GTP-Binding Proteins