Regulation of intrasteric inhibition of the multifunctional calcium/calmodulin-dependent protein kinase

Francisco H. Cruzalegui, Michael S. Kapiloff, John Paul Morfin, Bruce E. Kemp, Michael G. Rosenfeld, Anthony R. Means

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78 Scopus citations


A regulatory region involved in both autoinhibition and calmodulin (CaM) binding has previously been identified in the multifunctional Ca2+/CaM-dependent protein kinase (CaM kinase II). We have tested the role of various segments of the regulatory region in autoinhibition by the analysis of a series of truncation, substitution, and deletion mutants of the CaM kinase II α subunit (CaM kinase IIα). Unexpectedly, the sequence Lys-Lys-Phe-Asn at positions 291-294, adjacent to the CaM binding domain, was found to be sufficient to maintain an inhibited state in a truncated form of the kinase. However, these residues are not essential in the context of the full-length protein, indicating the importance of additional residues from the overlapping CaM binding domain. We propose here a molecular model for CaM kinase IIα based on the three-dimensional structure of the cAPK-PKI-(5-24) (protein kinase inhibitor fragment) complex. It is predicted from this model that autoinhibition is of the pseudosubstrate variety and that autophosphorylation of Thr-286 could occur by an intersubunit reaction in the holoenzyme complex.

Original languageEnglish (US)
Pages (from-to)12127-12131
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number24
StatePublished - 1992

ASJC Scopus subject areas

  • General


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