Molloy, Sean S. and Kennedy, Mary B. (1991) Autophosphorylation of type II Ca^(2+)/calmodulin-dependent protein kinase in cultures of postnatal rat hippocampal slices. Proceedings of the National Academy of Sciences of the United States of America, 88 (11). pp. 4756-4760. ISSN 0027-8424. http://resolver.caltech.edu/CaltechAUTHORS:20120424-154230067
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Autophosphorylation of Thr^(286) on type II Ca^(2+)/calmodulin-dependent protein kinase (CaM kinase) in vitro causes kinase activity to become partially independent of Ca^(2+). Here we report that Thr^(286) is the major CaM kinase autophosphorylation site occupied in situ in "organotypic" hippocampal cultures. Measurement of Ca^(2+)-independent CaM kinase activity revealed that approximately one-third of the kinase is autophosphorylated in situ when the basal Ca^(2+) concentration is 15-43 nM. This proportion was substantially reduced 30 min after removal of extracellular Ca^(2+) or treatment of the cultures with protein kinase inhibitors and was increased by treatment with okadaic acid. Therefore, the high proportion of autophosphorylated kinase at basal Ca^(2+) concentrations appears to be maintained by Ca^(2+)-dependent autophosphorylation. Homogenates of intact hippocampi also contain a high proportion of Ca^(2+)-independent type II CaM kinase, 13-23% depending on developmental age. Thus, in hippocampal neurons, an important function of the autophosphorylation mechanism may be to produce a relatively high level of CaM kinase activity, even at basal Ca^(2+) concentrations, permitting both upward and downward local regulation by physiological agents.
|Additional Information:||© 1991 National Academy of Sciences. Communicated by Masakazu Konishi, March 11, 1991. We thank Bruce Patton and Rich Mooney for their advice on various aspects of this work. We thank Wade Regehr and David Tank (AT & T Bell Laboratories) for measurements of Ca2+ concentration in our cultures. This work was supported by National Institutes of Health Grant NS17660 and Training Grant NS07251, the Beckman Institute, the Gustavus and Louise Pfeiffer Research Foundation, the Joseph W. Drown Foundation, the Irvine Foundation, and the McKnight Foundation. The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. §1734 solely to indicate this fact.|
|Subject Keywords:||synaptic regulation; molecular switch|
|Official Citation:||S S Molloy and M B Kennedy Autophosphorylation of type II Ca2+/calmodulin-dependent protein kinase in cultures of postnatal rat hippocampal slices PNAS 1991 88 (11) 4756-4760|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Melanie Stefan|
|Deposited On:||25 Apr 2012 18:08|
|Last Modified:||25 Apr 2012 18:08|
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