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Inhibition of calcium/calmodulin‐dependent protein kinase kinase (CaMKK) and calcium/calmodulin‐dependent protein kinase II (CaMKII) reduces colonic longitudinal muscle contraction by inhibition of myosin light chain kinase (MLCK)
Author(s) -
Anderson Charles,
Mahavadi Sunila,
Karnam Murthy,
Grider John
Publication year - 2011
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.25.1_supplement.1059.2
Subject(s) - myosin light chain kinase , calmodulin , myosin light chain phosphatase , contraction (grammar) , endocrinology , myosin , medicine , chemistry , rho associated protein kinase , muscle contraction , carbachol , calcium , protein kinase a , protein kinase c , kinase , biology , stimulation , biochemistry
Contraction of longitudinal muscle by a muscarinic agonist is regulated by the opposing actions of MLCK and myosin light chain phosphatase (MLCP) upon the phosphorylation level of the 20‐KDa subunit of myosin light chain. However, the signaling pathways leading to alterations of MLCK and MLCP activity are poorly understood. Aim To determine the role of CaMKK and CaMKII in the regulation of colonic longitudinal muscle contraction. Methods Longitudinal muscle‐myenteric plexus strips were prepared from rat colon for measurement of isometric contraction in organ chambers or used to prepare tissue lysates for immunokinase assay. Strips were exposed to CaMKK inhibitor STO‐609, or CaMKII inhibitor KN‐62, and carbachol (CCh; 0.01–100 uM) induced contraction or MLCK activity was measured and compared to control. Results CCh‐induced contraction in colonic longitudinal muscle was significantly attenuated by both STO‐609 (22–42% inhibition) and KN‐62 (42–49% inhibition). Consistent with their effect on contraction, STO‐609 and KN‐62 significantly reduced MLCK activity (68 and 64% inhibition, respectively) as measured by immunokinase assay. Conclusion Contraction of longitudinal muscle from rat colon in response to muscarinic receptor stimulation is mediated partly through activation of CaMKK and CaMKII. Supported by NIDDKD.