title: Anchoring of protein kinase A by ERM (ezrin-radixin-moesin) proteins is required for proper netrin signaling through DCC (deleted in colorectal cancer).
abstract: Netrin-1, acting through its principal receptor DCC (deleted in colorectal cancer), serves as an axon guidance cue during neural development and also contributes to vascular morphogenesis, epithelial migration, and the pathogenesis of some tumors. Several lines of evidence suggest that netrin-DCC signaling can regulate and be regulated by the cAMP-dependent protein kinase, PKA, although the molecular details of this relationship are poorly understood. Specificity in PKA signaling is often achieved through differential subcellular localization of the enzyme by interaction with protein kinase A anchoring proteins (AKAPs). Here, we show that AKAP function is required for DCC-mediated activation of PKA and phosphorylation of cytoskeletal regulatory proteins of the Mena/VASP (vasodilator-stimulated phosphoprotein) family. Moreover, we show that DCC and PKA physically interact and that this association is mediated by the ezrin-radixin-moesin (ERM) family of plasma membrane-actin cytoskeleton cross-linking proteins. Silencing of ERM protein expression inhibits DCC-PKA interaction, DCC-mediated PKA activation, and phosphorylation of Mena/VASP proteins as well as growth cone morphology and neurite outgrowth. Finally, although expression of wild-type radixin partially rescued growth cone morphology and tropism toward netrin in ERM-knockdown cells, expression of an AKAP-deficient mutant of radixin did not fully rescue growth cone morphology and switched netrin tropism from attraction to repulsion. These data support a model in which ERM-mediated anchoring of PKA activity to DCC is required for proper netrin/DCC-mediated signaling.
authors.affiliation: From the Department of Medical Laboratory and Radiation Sciences, the University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington Vermont 05405 and.
authors.forename: Paula B
authors.initials: PB
authors.lastname: Deming
authors.affiliation: the University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington Vermont 05405 and Department of Pharmacology, and the Department of Pharmacology, Université de Montréal, Montréal, Quebec H3C3J7 Canada.
authors.forename: Shirley L
authors.initials: SL
authors.lastname: Campbell
authors.affiliation: Department of Pharmacology, and.
authors.forename: Jamie B
authors.initials: JB
authors.lastname: Stone
authors.affiliation: Department of Pharmacology, and.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Rivard
authors.affiliation: Department of Pharmacology, and.
authors.forename: Alison L
authors.initials: AL
authors.lastname: Mercier
authors.affiliation: the University of Vermont Cancer Center, University of Vermont College of Medicine, Burlington Vermont 05405 and Department of Pharmacology, and Alan.Howe@uvm.edu.
authors.forename: Alan K
authors.initials: AK
authors.lastname: Howe
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism; D000818:Animals; D045744:Cell Line, Tumor; D002478:Cells, Cultured; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics / Q000378:metabolism*; D000075389:DCC Receptor; D005455:Fluorescent Antibody Technique; D057809:HEK293 Cells; D006801:Humans; D015151:Immunoblotting; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000494:pharmacology*; D000075388:Netrin-1; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000235:genetics; D011554:Pseudopodia / Q000235:genetics / Q000502:physiology; D034622:RNA Interference; D051381:Rats; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics; D025521:Tumor Suppressor Proteins / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D000099149:Ezrin
chemical_list: D017868:Cyclic AMP-Dependent Protein Kinases; D003598:Cytoskeletal Proteins; D000075389:DCC Receptor; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009414:Nerve Growth Factors; D000075388:Netrin-1; D011956:Receptors, Cell Surface; D025521:Tumor Suppressor Proteins; D000099149:Ezrin; C501909:DCC protein, human; C000617351:NTN1 protein, human; C000617354:Ntn1 protein, rat; C071058:moesin; C071776:radixin
keywords: A Kinase Anchoring Protein (AKAP); Axon Guidance; Cell Signaling; Deleted in Colorectal Cancer (DCC); Ezrin; Netrin; Neurite Outgrowth; Protein Kinase A (PKA)