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Published September 1988 | metadata_only
Journal Article

Sequences of autophosphorylation sites in neuronal type II CaM kinase that control Ca^(2+)-independent activity


After initial activation by Ca^(2+), the catalytic activity of type II Ca^(2+)/calmodulin-dependent protein kinase rapidly becomes partially independent of Ca^(2+). The transition is caused by autophosphorylation of a few subunits in the dodecameric holoenzyme, which is composed of varying proportions of two homologous types of subunits, alpha (50 kd) and beta (58-60 kd). We have identified one site in the alpha subunit (Thr286) and two in the beta subunit (Thr287 and Thr382) that are rapidly autophosphorylated. We show that phosphorylation of alpha-Thr286 and beta-Thr287, which are located immediately adjacent to the calmodulin binding domain, controls Ca^(2+)-independent activity. In contrast, phosphorylation of beta-Thr382 is not required to maintain Ca2+ independence. It is absent in the alpha subunit and is selectively removed from the minor beta' subunit, apparently by alternative splicing. Regulation of the presence of beta-Thr382 in the holoenzyme by both differential gene expression and alternative splicing suggests that it may have an important but highly specialized function.

Additional Information

Elsevier Copyright © 1988. Received 13 June 1988. Revised 19 July 1988. We thank Dr. Rudi Aebersold for advice during the early stages of this study and Dr. M. McMillan and L. Williams of the University of Southern California Comprehensive Cancer Center Microchemical Facility (Los Angeles, CA), Dr. E. Weber of the Vollum Institute for Advanced Biomedical Research, Oregon Health Sciences University (Portland, OR), and Dr. D. Teplow, J. Racs, and H. Wong of the California Institute of Technology Applied Microsequencing Facility !Pasadena, CA) for peptide sequencing and amino acid analysis. We also thank Caroline Bell for help with preparation of the manuscript. This work was supported by NIH grants NST7660 and NS07251. by the McKnight Foundation, and by the Epilepsy Foundation of America.

Additional details

August 19, 2023
August 19, 2023