ATPase activity of the microvillar 110 kDa polypeptide-calmodulin complex is activated in Mg2+ and inhibited in K+-EDTA by F-actin.
Highly purified microvillar 110 kDa polypeptide-calmodulin (110K-cam) complex was confirmed to have ATPase activities characteristic of a myosin. The effect of F-actin on these activities was investigated. The Mg2+-ATPase is activated about 2-fold by F-actin in a dose-dependent fashion, whereas the K+-EDTA-ATPase is inhibited by greater than 90% by F-actin. These data provide evidence for a functional relationship between the ATPase activity of 110K-cam and its interaction with F-actin. They also extend the similarities between 110K-cam and myosin. The results suggest that higher cells contain in addition to myosin a second class of myosin-like molecules represented by 110K-cam.
D000199:Actins / Q000494:pharmacology*; D000251:Adenosine Triphosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000818:Animals; D017301:Ca(2+) Mg(2+)-ATPase / Q000037:antagonists & inhibitors / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000037:antagonists & inhibitors; D002147:Calmodulin / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D007422:Intestines / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology*; D008871:Microvilli / Q000201:enzymology; D009218:Myosins / Q000378:metabolism; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits
D000199:Actins; D002147:Calmodulin; D011189:Potassium Chloride; D000251:Adenosine Triphosphatases; D017301:Ca(2+) Mg(2+)-ATPase; C026049:EDTA-ATPase; D009218:Myosins; D000252:Calcium-Transporting ATPases; D008274:Magnesium