Regulation of intrasteric inhibition of the multifunctional calcium/calmodulin-dependent protein kinase.
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 alpha subunit (CaM kinase II alpha). 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 II alpha 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.
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Related Subject Headings
- Structure-Activity Relationship
- Sequence Deletion
- Sequence Alignment
- Protein Structure, Tertiary
- Protein Kinases
- Protein Kinase Inhibitors
- Mutagenesis, Site-Directed
- Molecular Sequence Data
- Models, Molecular
- DNA Mutational Analysis
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Structure-Activity Relationship
- Sequence Deletion
- Sequence Alignment
- Protein Structure, Tertiary
- Protein Kinases
- Protein Kinase Inhibitors
- Mutagenesis, Site-Directed
- Molecular Sequence Data
- Models, Molecular
- DNA Mutational Analysis