title: Purification of an ATP-dependent actin-binding protein from a lower eukaryote, Physarum polycephalum.
abstract: A novel protein with a molecular mass of 55 kDa, as determined by SDS-PAGE, was purified from plasmodia of Physarum polycephalum. The protein bound to actin filaments with a stoichiometry of 0.27 moles per mole of actin with an apparent dissociation constant of 4 x 10(-8) M. In the presence of ATP, the protein dissociated from actin filaments. Adenosine 5-(gamma-thio)triphosphate and adenyl-5'-yl imidodiphosphate also abolished the actin-binding activity of the protein, but GTP did not. Because the cytoplasmic concentration of ATP oscillates in association with the shuttle streaming of the cytoplasm, it is possible that this protein might be involved in the actin-linked regulation of cytoplasmic streaming.
authors.affiliation: Department of Pharmacology, Gunma University School of Medicine, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Ishikawa
authors.forename: Y
authors.initials: Y
authors.lastname: Sasaki
authors.forename: A
authors.initials: A
authors.lastname: Nakamura
authors.forename: T
authors.initials: T
authors.lastname: Takagi
authors.forename: K
authors.initials: K
authors.lastname: Kohama
mesh_terms: D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D006160:Guanosine Triphosphate / Q000494:pharmacology; D008840:Microfilament Proteins / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D016839:Physarum polycephalum / Q000737:chemistry*; D012697:Serine Endopeptidases / Q000378:metabolism
chemical_list: D000199:Actins; D008840:Microfilament Proteins; D010446:Peptide Fragments; D000266:Adenylyl Imidodiphosphate; C022571:adenosine 5'-O-(3-thiotriphosphate); D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D012697:Serine Endopeptidases; C028344:glutamyl endopeptidase