Activation of calcium channels by cAMP in STC-1 cells is dependent upon Ca2+ calmodulin-dependent protein kinase II.

Published

Journal Article

Activation of L-type calcium channels in the neuroendocrine, cholecytstokinin-secreting cell line, STC-1, is vital for secretion of CCK. In the present study, the regulation of L-type Ca2+ channels by cAMP and Ca2+ calmodulin dependent protein kinase II (CaM-KII) in STC-1 cells was investigated. Exposure to 3-isobutyl-1-methylxanthine (IBMX) increased intracellular cAMP levels, whole cell Ca2+ currents and activated Ca2+ channels in cell-attached membrane patches. Furthermore, in Fura-2AM loaded cells, cytosolic Ca2+ levels increased upon exposure to IBMX. By contrast, pretreatment of cells with the CaM-KII inhibitor KN-62, prevented IBMX activation of Ca2+ channels in cell-attached patches or increases in cytosolic Ca2+ levels. Inclusion of the synthetic peptide fragment 290-309 of CaM-KII, a CaM-KII antagonist, in the pipette solution, blocked the activation of whole cell Ca2+ currents upon addition of IBMX. These results indicate a unique mechanism of L-type Ca2+ channel activation involving two phosphorylation events.

Full Text

Duke Authors

Cited Authors

  • Basavappa, S; Mangel, AW; Scott, L; Liddle, RA

Published Date

  • January 1999

Published In

Volume / Issue

  • 254 / 3

Start / End Page

  • 699 - 702

PubMed ID

  • 9920804

Pubmed Central ID

  • 9920804

Electronic International Standard Serial Number (EISSN)

  • 1090-2104

International Standard Serial Number (ISSN)

  • 0006-291X

Digital Object Identifier (DOI)

  • 10.1006/bbrc.1998.9997

Language

  • eng