A novel regulatory protein that affects the functions of caldesmon and myosin light chain kinase.
A caldesmon (CaD)-binding protein of about 65 kDa (by SDS-PAGE) was purified from smooth muscle of chicken gizzard. The 65-kDa protein prevented the inhibitory effect of CaD on the ATP-dependent interaction between actin and myosin. Unlike the case with calmodulin (CaM), Ca2+ was not required for this effect. As reported in the preceding communication, myosin light chain kinase (MLCK), another well characterized protein that binds CaM, has CaD-like activity that modulates the interaction by binding to actin. The 65-kDa protein was also effective in relieving the modulation, while leaving unaffected the kinase activity that phosphorylates the light chain of smooth muscle myosin.
Lin
Y
Y
Department of Pharmacology, Gunma University, School of Medicine, Japan.
Ishikawa
R
R
Kohama
K
K
D000199:Actins / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002148:Calmodulin-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002645:Chickens; D002848:Chromatography, DEAE-Cellulose; D004591:Electrophoresis, Polyacrylamide Gel; D005895:Gizzard, Avian / Q000201:enzymology / Q000378:metabolism; D007700:Kinetics; D008970:Molecular Weight; D009130:Muscle, Smooth / Q000201:enzymology / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D010766:Phosphorylation; D014462:Ultrafiltration
D000199:Actins; D002148:Calmodulin-Binding Proteins; D002352:Carrier Proteins; D000255:Adenosine Triphosphate; D009219:Myosin-Light-Chain Kinase; D009218:Myosins