Protein kinase A modulates an endogenous calcium channel, but not the calcium-activated chloride channel, in Xenopus oocytes

• Published in: FEBS letters 1993-12, Vol.336 (2), p.191-196
• Main Authors: Chen, Yan, Pollock, Jonathan D., Wang, Yuhuan, DePaoli-Roach, Anna A., Yu, Lei
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Calcium - metabolism; Calcium channel; Calcium Channels - metabolism; Calcium ionophore; Cattle; Cell membranes. Ionic channels. Membrane pores; Cell structures and functions; Chloride Channels - metabolism; Cyclic AMP - metabolism; Cyclic AMP-Dependent Protein Kinases - metabolism; Fundamental and applied biological sciences. Psychology; Molecular and cellular biology; Molecular Sequence Data; Phosphatase; Phosphoric Monoester Hydrolases - metabolism; Protein kinase A; Xenopus; Xenopus oocyte
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(93)80800-A

In Xenopus oocytes, Ca 2+ influx through an endogenous voltage-gated Ca 2+ channel activates a transient outward Cl − current ( I CI(Ca)), which is potentiated by cAMP increase. The site of cAMP effect appears to be the Ca 2+ channel instead of the Ca 2+-activated Cl − channel, because cAMP potentiates the Ba 2+ current through the Ca 2+ channel in a similar way to the I Cl(Ca), and cAMP does not potentiate the Ca 2+-dependent CI − current in cells treated with Ca 2+ ionophore. Using the catalytic subunit of protein kinase A (PKA) and PKA inhibitors, it was shown that PKA is both necessary and sufficient for the cAMP effect on I CI(Ca). Furthermore, the cAMP/PKA-mediated potentiation of I cI(Ca) was inhibited by both type 1 and type 2A protein phosphatases.