Premium
A calcium‐independent PKC isoform mediates cerebral vasoconstriction through actin cytoskeleton reorganization (841.2)
Author(s) -
ElYazbi Ahmed
Publication year - 2014
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.28.1_supplement.841.2
Subject(s) - protein kinase c , phosphorylation , myosin light chain kinase , vasoconstriction , microbiology and biotechnology , calcium , actin , chemistry , actin cytoskeleton , cytoskeleton , myosin , medicine , endocrinology , biophysics , biochemistry , biology , cell , organic chemistry
The role of PKC in force production and vasoconstriction in resistance arterioles is hypothesized to be through several mechanisms including: increased calcium influx, calcium sensitization, and thin filament regulation. PKC involvement in these pathways was proposed based on pharmacological experiments without direct biochemical measurement of the phosphoproteins. We studied the effect of phorbol dibutyrate (PDBu, 1 microM) on rat middle cerebral artery in a pressure myography setup. A slow profound constriction was obtained as a result of PDBu treatment. The constriction was associated with increased myosin light chain (LC20) phosphorylation that was similar to that evoked by a maximal dose of 5‐HT producing a smaller constriction. PDBu constrictions were abolished by GF109302X, but neither with a calcium‐dependent PKC inhibitor, nor with calcium‐free Krebs’, though the latter reduced LC20 phosphorylation. There was no evidence of increased phosphorylation of caldesmon and calponin, ruling out a role for thin filament regulation. G‐actin content was greatly reduced in both regular and calcium‐free Krebs’ solution together with an increase in paxillin phosphorylation in both conditions implicating actin cytoskeleton reorganization as a potential mechanism contributing to force generation independent of LC20 phosphorylation following PKC activation. Grant Funding Source : Supported by CIHR MOP‐97988