Regulation and function of Ca2+-calmodulin-dependent protein kinase II of fast-twitch rat skeletal muscle

Adam J. Rose, Thomas J. Alsted, J. Bjarke Kobberø, Erik A. Richter

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19 Citations (Scopus)

Abstract

The activation and function of Ca2+-calmodulin-dependent kinase II (CaMKII) in contracting rat skeletal muscle was examined. The increase in autonomous activity and phosphorylation at Thr287 of CaMKII of gastrocnemius muscle in response to contractions in situ was rapid and transient, peaking at 1-3 min, but reversed after 30 min of contractions. There was a positive correlation between CaMKII phosphorylation at Thr287 and autonomous CaMKII activity. In contrast to the rapid and transient increase in autonomous CaMKII activity, the phosphorylation of the putative CaMKII substrate trisk95/ triadin was rapid and sustained during contractions. There were no changes in CaMKII activity and phosphorylation or trisk95 phosphorylation in the resting contralateral muscles during stimulation. When fast-twitch muscles were contracted ex vivo, CaMKII inhibition resulted in a greater magnitude of fatigue as well as blunted CaMKII and trisk95 phosphorylation, identifying trisk95 as a physiological CaMKII substrate. In summary, skeletal muscle CaMKII activation was rapid and sustained during exercise/contraction and is mediated by factors within the contracting muscle, probably through allosteric activation via Ca2+-CaM. CaMKII may signal through trisk95 to modulate Ca2+ release in fast-twitch rat skeletal muscle during exercise/contraction.

Original languageEnglish
Pages (from-to)993-1005
Number of pages13
JournalJournal of Physiology
Volume580
Issue number3
DOIs
Publication statusPublished - 1 May 2007
Externally publishedYes

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