Regulation of the activities of multifunctional Ca2+/calmodulin-dependent protein kinases.
Ca2+/calmodulin-dependent protein kinases (CaM-kinases) II, IV, and I play important roles as Ca2+ responsive multifunctional protein kinases in controlling a variety of cellular functions in response to an increase in intracellular Ca2+, and hence regulation of their activities is very important. CaM-kinase II is activated through autophosphorylation of threonine-286 (in the case of alpha isoform), and CaM-kinases IV and I are activated through phosphorylation of threonine-196 and 177, respectively, by CaM-kinase kinase. After activation, CaM-kinases II and IV lose their Ca2+/calmodulin-dependent activity upon autophosphorylation of threonine-305 and serine-332, respectively, in the absence of Ca2+, becoming Ca2+/calmodulin-independent forms. The activated CaM-kinases II, IV, and I are deactivated upon dephosphorylation of phosphothreonine-286, 196, and 177, respectively, by CaM-kinase phosphatase or other multifunctional protein phosphatases and restored to the original ground states. Thus, the activities of the three multifunctional CaM-kinases are regulated by phosphorylation and dephosphorylation.
Fujisawa
H
H
Department of Biochemistry, Asahikawa Medical College, Asahikawa, Hokkaido 078-8510, Japan. fujisawa@asahikawa-med.ac.jp
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000145:classification / Q000378:metabolism*; D002540:Cerebral Cortex / Q000201:enzymology; D004789:Enzyme Activation / Q000502:physiology; D006801:Humans; D066298:In Vitro Techniques; D010749:Phosphoprotein Phosphatases / Q000378:metabolism*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000235:genetics* / Q000378:metabolism*; D013347:Subcellular Fractions / Q000502:physiology; D013950:Thymus Gland / Q000201:enzymology
D017346:Protein Serine-Threonine Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010749:Phosphoprotein Phosphatases; D002118:Calcium