Interaction of smooth muscle caldesmon with S-100 protein.
The interaction of caldesmon with certain Ca-binding proteins was investigated by means of electrophoresis under non-denaturating conditions. In the presence of Ca2+ calmodulin, troponin C and S-100 protein form a complex with caldesmon. No complex formation takes place in the absence of Ca2+. Lactalbumin and pike parvalbumin (pI4.2) do not interact with caldesmon independently of Ca-concentration. Both S-100 protein and calmodulin effectively inhibit phosphorylation of caldesmon by Ca-phospholipid-dependent protein kinase. At low ionic strength S-100 protein reverses the inhibitory action of caldesmon on the skeletal muscle acto-heavy meromyosin ATPase more effectively than calmodulin. It is supposed that in certain tissues and cell compartments the proteins belonging to the S-100 family are able to substitute for calmodulin in the caldesmon-dependent regulation of actin and myosin interaction.
Skripnikova
E V
EV
Department of Biochemistry, School of Biology, Moscow State University, USSR.
Gusev
N B
NB
D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D009130:Muscle, Smooth / Q000378:metabolism*; D009218:Myosins / Q000378:metabolism; D011485:Protein Binding; D011493:Protein Kinase C / Q000378:metabolism; D009418:S100 Proteins / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D002148:Calmodulin-Binding Proteins; D009418:S100 Proteins; D011493:Protein Kinase C; D009218:Myosins