title: Enhancement of GTP gamma S-binding activity by cAMP-dependent phosphorylation of a filamin-like 250 kDa membrane protein in human platelets.
abstract: The treatment of human platelets with the dibutyryl cyclic AMP (dbcAMP) revealed the presence of a 250 kDa protein which enhanced its GTP-binding activity. This protein was purified from platelet membranes by successive chromatographies on DEAE-cellulose, Ultrogel AcA34, Mono Q, HCA-hydroxyapatite, and TSK-3000SW columns. The positive cross-reaction of the 250 kDa protein with the anti-filamin antibody indicated that this protein is filamin or very close to it. The GTP gamma S-binding activity of this protein, when phosphorylated with cyclic AMP-dependent protein kinase (A-kinase), showed an over tenfold increase, with the specific activity being 3.6 nmol/mg protein. Dephosphorylation of the phosphorylated protein with alkaline phosphatase reduced the GTP gamma S-binding activity to the control untreated level.
authors.affiliation: Department of Biochemistry, Gifu University School of Medicine, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Yada
authors.forename: Y
authors.initials: Y
authors.lastname: Okano
authors.forename: Y
authors.initials: Y
authors.lastname: Nozawa
mesh_terms: D001792:Blood Platelets / Q000187:drug effects / Q000378:metabolism*; D002848:Chromatography, DEAE-Cellulose; D003285:Contractile Proteins / Q000097:blood* / Q000302:isolation & purification; D000242:Cyclic AMP / Q000097:blood*; D003599:Cytoskeleton / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D064448:Filamins; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000097:blood*; D006801:Humans; D007700:Kinetics; D008840:Microfilament Proteins / Q000097:blood* / Q000302:isolation & purification; D008970:Molecular Weight; D010766:Phosphorylation; D011485:Protein Binding; D011494:Protein Kinases / Q000097:blood*
chemical_list: D003285:Contractile Proteins; D064448:Filamins; D008840:Microfilament Proteins; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000242:Cyclic AMP; D011494:Protein Kinases