Calcium induces rapid changes in protein phosphorylation in permeabilized pancreatic acini.
Calcium is an important mediator of pancreatic stimulus-secretion coupling, and in streptolysin O-permeabilized acini maximal amylase release can be induced by 1 microMCa2+. Two-dimensional analysis of acinar phosphoproteins using 32P-labeled acini showed that 1-min stimulation of permeabilized acini with 1 microMCa2+ induced a number of rapid protein phosphorylation and dephosphorylation events similar to previously observed effects of secretagogues acting on intact acini. The rapid Ca2+ effects on protein phosphorylation correlated well with the earliest detectable onset of amylase release after 1 min of incubation with Ca2+. Our findings indicate that some of the agonist-induced changes in protein phosphorylation are mediated by Ca2+ and also provide evidence for the possible involvement of Ca(2+)-mediated dephosphorylation in acinar stimulus-secretion coupling.
Wagner
A C
AC
Department of Physiology, University of Michigan, Ann Arbor 48109-0622, USA.
Williams
J A
JA
D000681:Amylases / Q000378:metabolism; D000818:Animals; D001426:Bacterial Proteins; D002118:Calcium / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000502:physiology; D015180:Electrophoresis, Gel, Two-Dimensional; D008297:Male; D010179:Pancreas / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013301:Streptolysins / Q000494:pharmacology
D001426:Bacterial Proteins; D010750:Phosphoproteins; D013301:Streptolysins; C025964:streptolysin O; D000681:Amylases; D002118:Calcium