Expression of a multifunctional Ca2+/calmodulin-dependent protein kinase and mutational analysis of its autoregulation

Phyllis I. Hanson, Michael S. Kapiloff, Lillian L. Lou, Michael G. Rosenfeld, Howard Schulman

Research output: Contribution to journalArticlepeer-review

228 Scopus citations


Autophosphorylation of multifunctional Ca2+/calmod-ulin-dependent protein kinase converts it from a Ca2+-dependent to a Ca2+-independent or autonomous kinase, a process that may underlie some long-term enhancement of transient Ca2+ signals. We demonstrate that the neuronal α subunit clone expressed in COS-7 cells (α-CaM kinase) is sufficient to encode the regulatory phenomena characteristic of the multisubunit kinase isolated from brain. Activity of α-CaM kinase is highly dependent on Ca2+/calmodulin. It is converted by autophosphorylation to an enzyme capable of Ca2+-independent (autonomous) substrate phosphorylation and autophosphorylation. Using site-directed mutagenesis, we separately eliminate five putative auto-phosphorylation sites within the regulatory domain and directly examine their individual roles. Ca2+/calmodulin-dependent kinase activity is fully retained by each mutant, but Thr286 is unique among the sites in being indispensable for generation of an autonomous kinase.

Original languageEnglish (US)
Pages (from-to)59-70
Number of pages12
Issue number1
StatePublished - Jul 1989

ASJC Scopus subject areas

  • Neuroscience(all)


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