Regulation of Ca2+/calmodulin-dependent protein kinase IV (CaM-kinase IV) by changing its susceptibility to phosphorylation by CaM-kinase kinases.
Calmodulin-dependent protein kinase IV (CaM-kinase IV) is markedly activated on the phosphorylation of Thr196 by an upstream protein kinase, CaM-kinase kinase. The phosphorylation of CaM-kinase IV by CaM-kinase kinase is strongly suppressed on incubation with calmodulin in the presence of Ca2+, which results in a decrease in the enzyme activity, and completely restored on subsequent incubation with Mg2+ in the absence of Ca2+, which results in an increase in the activity. That a downstream protein kinase regulates its activity through reversible changes in its susceptibility to phosphorylation by an upstream protein kinase is a new regulatory mechanism.
Okuno
S
S
Department of Biochemistry, Asahikawa Medical College, Hokkaido.
Kitani
T
T
Fujisawa
H
H
D000818:Animals; D001921:Brain / Q000378:metabolism; D002118:Calcium / Q000494:pharmacology; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism*; D002147:Calmodulin / Q000494:pharmacology; D002645:Chickens; D004789:Enzyme Activation / Q000187:drug effects; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D013912:Threonine / Q000378:metabolism
D002147:Calmodulin; D013912:Threonine; D017346:Protein Serine-Threonine Kinases; D054737:Calcium-Calmodulin-Dependent Protein Kinase Kinase; D054734:Calcium-Calmodulin-Dependent Protein Kinase Type 4; D017871:Calcium-Calmodulin-Dependent Protein Kinases; C517686:Camk4 protein, rat; D002118:Calcium