title: Rho/ROCK and Cdk5 effects on phosphorylation of a beta-thymosin repeat protein in Hermissenda.
abstract: Rho GTPases acting through effector proteins regulate actin dynamics and cytoskeletal structure. In Hermissenda Csp24 is a cytoskeletal-related protein that contributes to the development of intermediate-term memory, and is homologous to other beta-thymosin-like repeat proteins containing multiple actin-binding domains. We have examined the role of Rho GTPase activity and its downstream target ROCK, and cyclin-dependent kinase 5 (Cdk5) on the phosphorylation of Csp24 using 32PO4 labeling of proteins separated with 2-D PAGE. The ROCK inhibitor Y-27632 significantly increased Csp24 phosphorylation, and the Rho activator lysophosphatidic acid (LPA) or the Cdk5 inhibitor butyrolactone significantly decreased Csp24 phosphorylation. Pretreatment with Y-27632 before LPA application significantly reduced the decreased phosphorylation of Csp24 normally detected in nervous systems exposed to LPA. Using a pull-down assay we found that LPA treatments activated Rho and exposure to 5-HT decreased Rho activity. Our results indicate that the Rho/ROCK and Cdk5 signaling pathways contribute to the regulation of Csp24 phosphorylation.
authors.affiliation: Department of Neurobiology and Anatomy, University of Texas Medical School, Houston, TX 77030, USA. terry.crow@uth.tmc.edu
authors.forename: Terry
authors.initials: T
authors.lastname: Crow
authors.forename: Juan-Juan
authors.initials: JJ
authors.lastname: Xue-Bian
authors.forename: Pramod K
authors.initials: PK
authors.lastname: Dash
authors.forename: Lian-Ming
authors.initials: LM
authors.lastname: Tian
mesh_terms: D000577:Amides / Q000494:pharmacology; D000818:Animals; D002090:Butyrophenones / Q000494:pharmacology; D051360:Cyclin-Dependent Kinase 5; D018844:Cyclin-Dependent Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008246:Lysophospholipids / Q000494:pharmacology; D008840:Microfilament Proteins / Q000378:metabolism*; D008974:Mollusca / Q000201:enzymology*; D009420:Nervous System / Q000187:drug effects / Q000201:enzymology; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors; D011725:Pyridines / Q000494:pharmacology; D013947:Thymosin / Q000031:analogs & derivatives / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000819:agonists / Q000378:metabolism*; D054460:rho-Associated Kinases
chemical_list: D000577:Amides; D002090:Butyrophenones; C474106:Csp24 protein, Hermissenda; D047908:Intracellular Signaling Peptides and Proteins; D008246:Lysophospholipids; D008840:Microfilament Proteins; D010750:Phosphoproteins; D011725:Pyridines; C108830:Y 27632; D013947:Thymosin; D051360:Cyclin-Dependent Kinase 5; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D018844:Cyclin-Dependent Kinases; D020741:rho GTP-Binding Proteins; C032881:lysophosphatidic acid