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Ca 2+ –calmodulin‐dependent protein kinase expression and signalling in skeletal muscle during exercise
Author(s) -
Rose Adam J.,
Kiens Bente,
Richter Erik A.
Publication year - 2006
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2006.111757
Subject(s) - skeletal muscle , phospholamban , camk , medicine , endocrinology , phosphorylation , chemistry , physical exercise , calmodulin , protein kinase a , kinase , biology , calcium , biochemistry , autophosphorylation
Ca 2 + signalling is proposed to play an important role in skeletal muscle function during exercise. Here, we examined the expression of multifunctional Ca 2 + –calmodulin‐dependent protein kinases (CaMK) in human skeletal muscle and show that CaMKII and CaMKK, but not CaMKI or CaMKIV, are expressed. Furthermore, the effect of exercise duration and intensity on skeletal muscle CaMKII activity and phosphorylation of downstream targets was examined. Eight healthy men exercised at ∼67% of peak pulmonary O 2 uptake with muscle samples taken at rest and after 1, 10, 30, 60 and 90 min of exercise. Ten other men exercised for three consecutive 10 min bouts at 35%, 60% and 85% with muscle samples taken at rest, at the end of each interval and 30 min post‐exercise. There was a rapid and transient increase in autonomous CaMKII activity and CaMKII phosphorylation at Thr 287 in skeletal muscle during exercise. Furthermore, the phosphorylation of phospholamban (PLN) at Thr 17 , which was identified as a CaMKII substrate in skeletal muscle, was rapidly (< 1 min) increased by exercise, and remained phosphorylated 5‐fold above basal level during 90 min of exercise. The phosphorylation of serum response factor at Ser 103 , a putative CaMKII substrate, was higher after 30 min of exercise. PLN phosphorylation at Thr 17 was higher with increasing exercise intensities. These data indicate that CaMKII is the major multifunctional CaMK in skeletal muscle and its activation occurs rapidly and is sustained during continuous exercise, with the activation being greater during intense exercise.