title: Protein Kinase C Phosphorylation of a γ-Protocadherin C-terminal Lipid Binding Domain Regulates Focal Adhesion Kinase Inhibition and Dendrite Arborization.
abstract: The γ-protocadherins (γ-Pcdhs) are a family of 22 adhesion molecules with multiple critical developmental functions, including the proper formation of dendritic arbors by forebrain neurons. The γ-Pcdhs bind to and inhibit focal adhesion kinase (FAK) via a constant C-terminal cytoplasmic domain shared by all 22 proteins. In cortical neurons lacking the γ-Pcdhs, aberrantly high activity of FAK and of PKC disrupts dendrite arborization. Little is known, however, about how γ-Pcdh function is regulated by other factors. Here we show that PKC phosphorylates a serine residue situated within a phospholipid binding motif at the shared γ-Pcdh C terminus. Western blots using a novel phospho-specific antibody against this site suggest that a portion of γ-Pcdh proteins is phosphorylated in the cortex in vivo. We find that PKC phosphorylation disrupts both phospholipid binding and the γ-Pcdh inhibition of (but not binding to) FAK. Introduction of a non-phosphorylatable (S922A) γ-Pcdh construct into wild-type cortical neurons significantly increases dendrite arborization. This same S922A construct can also rescue dendrite arborization defects in γ-Pcdh null neurons cell autonomously. Consistent with these data, introduction of a phosphomimetic (S/D) γ-Pcdh construct or treatment with a PKC activator reduces dendrite arborization in wild-type cortical neurons. Together, these data identify a novel mechanism through which γ-Pcdh control of a signaling pathway important for dendrite arborization is regulated.
authors.affiliation: Department of Biology, The University of Iowa, Iowa City, Iowa 52242; Neuroscience Graduate Program, The University of Iowa, Iowa City, Iowa 52242.
authors.forename: Austin B
authors.initials: AB
authors.lastname: Keeler
authors.affiliation: Department of Biology, The University of Iowa, Iowa City, Iowa 52242.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schreiner
authors.affiliation: Department of Biology, The University of Iowa, Iowa City, Iowa 52242; Neuroscience Graduate Program, The University of Iowa, Iowa City, Iowa 52242. Electronic address: joshua-weiner@uiowa.edu.
authors.forename: Joshua A
authors.initials: JA
authors.lastname: Weiner
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000070585:Cadherin Related Proteins; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002540:Cerebral Cortex / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism* / Q000648:ultrastructure; D003712:Dendrites / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D004622:Embryo, Mammalian; D051417:Focal Adhesion Kinase 1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D055495:Neurogenesis / Q000235:genetics*; D010716:Phosphatidylinositols / Q000378:metabolism; D010766:Phosphorylation; D061251:Primary Cell Culture; D011485:Protein Binding; D011493:Protein Kinase C / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D000070585:Cadherin Related Proteins; D015820:Cadherins; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C504472:Pcdhgc3 protein, mouse; D010716:Phosphatidylinositols; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D051417:Focal Adhesion Kinase 1; C496051:Ptk2 protein, mouse; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate
keywords: Pcdh; branching; cell adhesion; cortex; dendrite; dendritogenesis; phosphorylation; serine/threonine protein kinase; signaling