title: Coordinate release of myosin and a high molecular weight microtubule-associated protein from PC12 cytoskeletons by ATP.
abstract: The association of two high molecular weight (HMW) structural proteins with the cytoskeletons of rat pheochromocytoma cells, PC12, is regulated by ATP and other nucleotides. Exposure of PC12 cytoskeletons to ATP resulted in the selective solubilization of two HMW proteins, identified as myosin and a 280 kD microtubule-associated protein. These two proteins were rapidly released from the cytoskeleton following incubation with ATP, GTP, CTP, and ADP; non-hydrolysable ATP analog caused protein release to a less marked extent. The effect of the latter two nucleotides indicated that the release of the myosin and the HMW microtubule-associated protein was likely to be the result of nucleotide-induced conformational changes in one or both proteins. Myosin and the HMW microtubule-associated proteins interact with actin in vitro in a nucleotide-sensitive manner. The present data demonstrate that similar interactions are likely to exist within the intact cytoskeleton and suggest that the associations of these structural proteins with the cytoskeleton are regulated by common mechanisms. The results also suggest that the cells may differentially regulate the stability of a subset of these structural proteins in their interactions with other cytoskeletal elements.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000310:Adrenal Gland Neoplasms / Q000648:ultrastructure*; D000818:Animals; D002642:Chick Embryo; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D008869:Microtubule-Associated Proteins / Q000378:metabolism*; D008970:Molecular Weight; D009218:Myosins / Q000378:metabolism*; D009711:Nucleotides / Q000494:pharmacology; D017830:Octoxynol; D010673:Pheochromocytoma / Q000648:ultrastructure*; D011092:Polyethylene Glycols / Q000494:pharmacology; D012995:Solubility; D013379:Substrate Specificity
chemical_list: D008869:Microtubule-Associated Proteins; D009711:Nucleotides; D011092:Polyethylene Glycols; D000255:Adenosine Triphosphate; D017830:Octoxynol; D009218:Myosins