Premium
Agonist‐Induced Rho Kinase and ZIP kinase Activity Levels in Different Regions of the Stomach
Author(s) -
AlShboul Othman,
Bhattacharya Sayak,
Mahavadi Sunila,
Murthy Karnam S.
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.1059.3
Subject(s) - phosphatase , kinase , stimulation , biology , rho associated protein kinase , tonic (physiology) , cyclin dependent kinase 9 , mitogen activated protein kinase kinase , chemistry , microbiology and biotechnology , protein kinase a , endocrinology , phosphorylation
The molecular events that regulate the tonic and phasic phenotypes of smooth muscle are attributed to differential expression of contractile proteins and signaling pathway that regulate MLC kinase and MLC phosphatase activity, and thus MLC 20 phosphorylation. The activity of MLC phosphatase is inhibited by Rho kinase/ZIP kinase‐dependent pathways. AIM To determine whether Rho kinase and ZIP kinase activity levels correlate with the contractile phenotypes in proximal (tonic) versus distal (phasic) stomach. METHODS Muscle cells were isolated separately from proximal and distal regions of rabbit stomach. Acetylcholine (ACh)‐induced stimulation of Rho kinase and ZIP kinase activity was determined by immunokinase assay. RESULTS ACh (0.1 μM) caused stimulation of Rho kinase and ZIP kinase activity in muscle cells of both proximal and distal stomach. However, stimulation of both kinases was significantly higher in muscle cells from proximal stomach compared to distal stomach. Y27632, a selective blocker of Rho kinase, inhibited stimulation of ZIP kinase activity suggesting that stimulation of ZIP kinase activity is dependent on Rho kinase activity. CONCLUSION Higher activity levels of Rho kinase and ZIP kinase, which normally inhibit MLC phosphatase and increase MLC 20 phosphorylation, in proximal stomach correlate with its tonic phenotype compared to the distal stomach that exhibits phasic phenotype.