title: Existence of multiple phosphorylated forms of human platelet actin binding protein.
abstract: Platelet actin binding protein (ABP) as isolated from human platelets exists in at least four phosphorylated forms which we have designated ABP-0, ABP-1, ABP-2, and ABP-3 whose phosphate content ranges from 18 (ABP-0) to 40 (ABP-3) moles Pi/mole ABP. These forms differ in their resistance to calpain cleavage and ability to cross-link F-actin with ABP-3 being the best in each of these properties. Attempts to phosphorylate ABP-1, two or three with protein kinase C (PKC) were unsuccessful except if the proteins were pretreated with Escherichia coli alkaline phosphatase. All of the forms could be phosphorylated with cAMP-dependent kinase (PKA) and subsequent resistance to calpain cleavage conferred. Phosphorylation/dephosphorylation of ABP may be an important regulatory mechanism by which the cytoskeletal architecture is stabilized or transformed.
authors.affiliation: Department of Biochemistry, State University of New York Health Science Center at Brooklyn 11203.
authors.forename: M P
authors.initials: MP
authors.lastname: Wu
authors.forename: D
authors.initials: D
authors.lastname: Jay
authors.forename: A
authors.initials: A
authors.lastname: Stracher
mesh_terms: D000199:Actins / Q000378:metabolism*; D001792:Blood Platelets / Q000201:enzymology*; D002154:Calpain; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism
chemical_list: D000199:Actins; D008840:Microfilament Proteins; D017868:Cyclic AMP-Dependent Protein Kinases; D011493:Protein Kinase C; D002154:Calpain