Mechanical force activates eIF-2alpha phospho-kinases in fibroblast.
Mechanical forces can induce differentiation of fibroblasts into myofibroblasts, a process which requires activation of the MAP kinase p38. Currently, the identification of other phospho-kinases involved in myofibroblast differentiation has not been explored. We applied static tensile forces to rat cardiac fibroblasts via collagen-coated magnetite beads and examined activation of protein phospho-kinases by the Kinexus phospho-antibody screening system. Of 75 candidate protein kinases screened, 39 were detected and, of these, 31 phospho-kinases were analyzed. Following force application, 12 out of 31 phospho-kinases exhibited increases of phosphorylation including PKR (>4-fold), MKK3 (3-fold), MKK6 ( approximately 2-fold), and p38 ( approximately 2-fold). In several types of mechanically sensitive, contractile fibroblasts including rat cardiac, human gingival, and Rat-2 fibroblasts, tensile forces increased eIF-2alpha phosphorylation, a downstream effector of PKR. We conclude that phospho-antibody screening is an efficient method for discovery of novel mechanical force-induced phospho-kinases and force can activate eIF-2alpha phospho-kinases in fibroblasts.
Wang
J
J
CIHR Group in Matrix Dynamics, Faculty of Dentistry, University of Toronto, Toronto, Ont., Canada.
Laschinger
Carol
C
Zhao
Xiao Han
XH
Mak
Baldwin
B
Seth
A
A
McCulloch
C A
CA
D000818:Animals; D004789:Enzyme Activation; D015852:Eukaryotic Initiation Factor-2 / Q000378:metabolism*; D005347:Fibroblasts / Q000201:enzymology; D006801:Humans; D009206:Myocardium / Q000166:cytology / Q000201:enzymology / Q000378:metabolism; D010766:Phosphorylation; D010770:Phosphotransferases / Q000378:metabolism*; D010812:Physical Stimulation; D051381:Rats
D015852:Eukaryotic Initiation Factor-2; D010770:Phosphotransferases