Protein kinase C activates capacitative calcium entry in the insulin secreting cell line RINm5F

FEBS Lett. 1994 Feb 21;339(3):307-11. doi: 10.1016/0014-5793(94)80436-2.

Abstract

This study examines the calcium store-regulated (capacitative) calcium influx pathway in the endocrine pancreatic cell line RINm5F, utilizing thapsigargin. After preincubation of the cells with the phorbol ester TPA, thapsigargin induced a sustained elevation of cytosolic calcium as well as a sustained stimulation of manganese entry, the latter being used to assess calcium influx. Thapsigargin given alone provoked a smaller and only transient elevation of cytosolic calcium and stimulation of manganese entry. The protein kinase C inhibitor staurosporine antagonized the effect of the phorbol ester. Verapamil, nifedipine, or measures to hyperpolarize the cells exerted no inhibitory action against this effect, which excludes an involvement of voltage-dependent calcium channels. In conclusion, our data shows for the first time that protein kinase C stimulation activates the capacitative calcium influx pathway of endocrine pancreatic insulin-producing cells.

MeSH terms

  • Alkaloids / pharmacology
  • Animals
  • Biological Transport / drug effects
  • Calcium / metabolism*
  • Cytosol / metabolism
  • Insulin / metabolism*
  • Insulin Secretion
  • Insulinoma / metabolism*
  • Manganese / metabolism
  • Pancreatic Neoplasms / metabolism*
  • Protein Kinase C / antagonists & inhibitors
  • Protein Kinase C / metabolism*
  • Rats
  • Staurosporine
  • Terpenes / pharmacology
  • Tetradecanoylphorbol Acetate / pharmacology
  • Thapsigargin
  • Tumor Cells, Cultured

Substances

  • Alkaloids
  • Insulin
  • Terpenes
  • Manganese
  • Thapsigargin
  • Protein Kinase C
  • Staurosporine
  • Tetradecanoylphorbol Acetate
  • Calcium