title: Laminin-mediated process formation in neuronal cells involves protein dephosphorylation.
abstract: Laminin mediates neural adhesion and process formation. A possible signal transduction pathway for laminin was investigated in both NG108-15 and PC12 neuronal cells using radiolabeling studies as well as various stimulators and inhibitors of phosphatases and kinases. Using [32P]-ortho-phosphate, laminin caused a decrease in the TCA-precipitable counts. Further, laminin stimulated dephosphorylation of laminin binding proteins of 110 kDa, 67 kDa, and 45 kDa and this dephosphorylation was blocked by the phosphatase inhibitor, okadaic acid, and the protein kinase C stimulator, TPA. The phosphatase inhibitors okadaic acid and vanadate, as well as the protein kinase C stimulators, TPA and DAG, blocked laminin-mediated process formation. Inhibitors of kinase activity such as H-7, H-8, and H-9 increased laminin-mediated neural process formation. Since phosphate incorporation into laminin-binding proteins is decreased by laminin and because both phosphatase inhibitors and kinase stimulators inhibit laminin-mediated process formation, we conclude that dephosphorylation events promote the neural cell response to laminin.
authors.affiliation: Laboratory of Developmental Biology and Anomalies, National Institute of Dental Research National Institutes of Health, Bethesda, Maryland.
authors.forename: B S
authors.initials: BS
authors.lastname: Weeks
authors.forename: J
authors.initials: J
authors.lastname: DiSalvo
authors.forename: H K
authors.initials: HK
authors.lastname: Kleinman
mesh_terms: D000310:Adrenal Gland Neoplasms / Q000473:pathology; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D004075:Diglycerides / Q000494:pharmacology; D004988:Ethers, Cyclic / Q000494:pharmacology; D005910:Glioma / Q000473:pathology; D007797:Laminin / Q000494:pharmacology*; D009363:Neoplasm Proteins / Q000378:metabolism; D009447:Neuroblastoma / Q000473:pathology; D009474:Neurons / Q000187:drug effects* / Q000648:ultrastructure; D019319:Okadaic Acid; D010673:Pheochromocytoma / Q000473:pathology; D010703:Phorbol Esters / Q000494:pharmacology; D010749:Phosphoprotein Phosphatases / Q000378:metabolism; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects*; D051381:Rats; D015398:Signal Transduction; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000648:ultrastructure; D014638:Vanadates / Q000494:pharmacology
chemical_list: D004075:Diglycerides; D004988:Ethers, Cyclic; D007797:Laminin; D009363:Neoplasm Proteins; D010703:Phorbol Esters; D010750:Phosphoproteins; C044295:1,2-dioctanoylglycerol; D019319:Okadaic Acid; D014638:Vanadates; D011493:Protein Kinase C; D010749:Phosphoprotein Phosphatases