Acyl-Coenzyme A Causes Ca2+Release in Pancreatic Acinar Cells

Timothy J. Fitzsimmons, James A. McRoberts, Ken H. Tachiki, Stephen J. Pandol
1997 Journal of Biological Chemistry  
The regulation of cytosolic Ca 2؉ is important for a variety of cell functions. One non-inositol 1,4,5-trisphosphate (IP 3 ) compound that may regulate Ca 2؉ is palmitoyl-coenzyme A (CoA), a fatty acid-CoA that is reported to cause Ca 2؉ release from intracellular stores of oocytes, myocytes, and hepatocytes. To study the role of palmitoyl-CoA in the pancreatic acinar cell, rat pancreatic acini were isolated by collagenase digestion, permeablized with streptolysin O, and the release of Ca 2؉
more » ... m internal stores was measured with fura-2. Palmitoyl-CoA released Ca 2؉ from internal stores (EC 50 ‫؍‬ 14 M). The palmitoyl-CoA-sensitive pool was distinct from, and overlapping with the IP 3 -sensitive Ca 2؉ pool. The effects of submaximal doses of IP 3 or cyclic ADP-ribose plus palmitoyl-CoA were additive. Fatty acid-CoA derivatives with carbon chain lengths of 16 -18 were the most potent and efficacious. Ryanodine and caffeine or elevated resting [Ca 2؉ ] sensitized the Ca 2؉ pool to the actions of palmitoyl-CoA. Fatty acid-CoA levels in pancreatic acini were measured by extraction with 2-propanol/ acetonitrile, followed by separation and quantification using reverse phase high performance liquid chromatography, and were found to be 10.17 ؎ 0.93 nmol/mg protein. These data suggest the presence of an IP 3 -insensitive palmitoyl-CoA-sensitive Ca 2؉ store in pancreatic acinar cells and suggest that palmitoyl-CoA may be needed for Ca 2؉ -induced Ca 2؉ release.
doi:10.1074/jbc.272.50.31435 pmid:9395476 fatcat:qv33eorv6jggnfi3bcvvcm4rj4