Binding of calmodulin to the neuronal cytoskeletal protein kinase type II cooperatively stimulates autophosphorylation

H. Le Vine, N. E. Sahyoun, P. Cuatrecasas

Research output: Contribution to journalArticlepeer-review

23 Scopus citations


The kinetics of autophosphorylation of the cytoskeletal form of the neuronal calmodulin-dependent protein kinase type II were studied as a function of calmodulin binding under the same conditions. Whereas calmodulin binding was noncooperative with respect to calmodulin concentration (Hill coefficient = 1), the activation of autophosphorylation and the phosphorylation of exogenous substrates showed marked positive cooperativity (Hill coefficient ≥ 1.6). Reduction of the active calmodulin concentration by the addition of the calmodulin antagonist trifluoperazine confirmed the cooperative nature of enzyme activation, because autophosphorylation was more sensitive to the drug than was binding at high concentrations of calmodulin. At intracellular levels of calmodulin the binding and activation of autophosphorylation were cooperative functions of magnesium and calcium concentration. The calmodulin-dependent cooperative activation seems to be a unique feature of the cytoskeletal, but not the soluble, form of the protein kinase and may result from the supramolecular organization of the cytoskeletal enzyme. These observations suggest that interactions among the subunits of the oligomeric cytoskeletal calmodulin-dependent protein kinase regulate enzyme activation, enhancing the sensitivity of the enzyme to small changes in the intracellular calcium levels that may be particularly relevant to signaling at the synapse.

Original languageEnglish
Pages (from-to)2253-2257
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number7
StatePublished - 1986

ASJC Scopus subject areas

  • General


Dive into the research topics of 'Binding of calmodulin to the neuronal cytoskeletal protein kinase type II cooperatively stimulates autophosphorylation'. Together they form a unique fingerprint.

Cite this