title: Calcium-sensitive regulation of actin-myosin interactions in baby hamster kidney (BHK-21) cells.
abstract: A fraction has been obtained from baby hamster kidney (BHK-21) cells that will stimulate the actin-moderated ATPase (ATP phosphohydrolase, EC 3.6.1.3) activity of both BHK-21 myosin and gizzard smooth muscle myosin. This activation is associated with the specific phosphorylation of the myosin 20,000-dalton light chain. The BHK-21 myosin light chain kinase preparation contains a major protein of approximately 105,000 molecular weight as determined by sodium dodecyl sulfate gel electrophoresis. Both the actin activation and phosphorylation events require the presence of Ca2+ and the so-called modulator or calcium-dependent regulator protein that has been isolated from smooth muscle, brain, and other tissues. On the basis of these results we propose that this kinase system constitutes a Ca2+-dependent regulatory mechanism for myosin-actin interactions in nonmuscle mammalian cells.
mesh_terms: D000199:Actins / Q000378:metabolism*; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002460:Cell Line; D002465:Cell Movement; D006224:Cricetinae; D007668:Kidney; D046911:Macromolecular Substances; D008970:Molecular Weight; D009130:Muscle, Smooth / Q000378:metabolism; D009218:Myosins / Q000378:metabolism*; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism
chemical_list: D000199:Actins; D046911:Macromolecular Substances; D011494:Protein Kinases; D000251:Adenosine Triphosphatases; D009218:Myosins; D002118:Calcium