Ca 2+/calmodulin-dependent protein kinase kinase β is regulated by multisite phosphorylation

Michelle F. Green, John W. Scott, Rohan Steel, Jonathan S. Oakhill, Bruce E. Kemp, Anthony R. Means

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48 Citations (Scopus)


Ca 2+/calmodulin-dependent protein kinase kinase β (CaMKKβ) is a serine/threonine-directed kinase that is activated following increases in intracellular Ca2+. CaMKKβ activates Ca2+/calmodulin-dependent protein kinase I, Ca2+/calmodulin-dependent protein kinase IV, and the AMP-dependent protein kinase in a number of physiological pathways, including learning and memory formation, neuronal differentiation, and regulation of energy balance. Here, we report the novel regulation of CaMKKβ activity by multisite phosphorylation. We identify three phosphorylation sites in the N terminus of CaMKKβ, which regulate its Ca2+/calmodulin-independent autonomous activity. We then identify the kinases responsible for these phosphorylations as cyclin-dependent kinase 5 (CDK5) and glycogen synthase kinase 3 (GSK3). In addition to regulation of autonomous activity, we find that phosphorylation of CaMKKβ regulates its half-life. We find that cellular levels of CaMKKβ correlate with CDK5 activity and are regulated developmentally in neurons. Finally, we demonstrate that appropriate phosphorylation of CaMKKβ is critical for its role in neurite development. These results reveal a novel regulatory mechanism for CaMKKβ-dependent signaling cascades.

Original languageEnglish
Pages (from-to)28066-28079
Number of pages14
JournalJournal of Biological Chemistry
Issue number32
Publication statusPublished - 12 Aug 2011
Externally publishedYes

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