Rw. Wrenn et al., BETA-1 INTEGRIN LIGATION STIMULATES TYROSINE PHOSPHORYLATION OF PHOSPHOLIPASE C-GAMMA-1 AND ELEVATES INTRACELLULAR CA2-CELLS( IN PANCREATICACINAR), Biochemical and biophysical research communications, 226(3), 1996, pp. 876-882
We have recently reported increased tyrosine (TYR) phosphorylation of
a number of pancreatic acinar cell proteins following antibody ligatio
n of beta 1 integrins (Wrenn and Herman, Biochem. Biophys. Res. Commun
. 208, 1995, 978-984). Concurrent with this TYR phosphorylation was a
marked activation of protein kinase C (PKC). This led us to investigat
e phospholipase C gamma 1 (PLC gamma 1),a key enzyme responsible for d
iacylglycerol generation, as a target for integrin-mediated TYR phosph
orylation. Staining with antiphosphotyrosine antibodies revealed incre
ased TYR phosphorylation of immunoprecipitated PLC gamma 1 prepared fr
om beta 1 integrin-ligated acinar cells. Subsequent stripping and repr
obing of Western blots with polyclonal anti-PLC gamma 1 was confirmato
ry. Over this same time period, intracellular [Ca2+] increased from <1
00 nM to 600 nM, further suggesting a functional relevance of integrin
-linked phosphorylation as a regulatory mechanism in exocrine pancreas
. (C) 1996 Academic Press, Inc.