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A potential site of functional modulation by protein kinase A in the cardiac Ca 2+ channel α 1C subunit
Author(s) -
Perets Tuvia,
Blumenstein Yakov,
Shistik Elena,
Lotan Ilana,
Dascal Nathan
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)00303-1
Subject(s) - xenopus , protein subunit , protein kinase a , phosphorylation , serine , chemistry , alanine , biophysics , kinase , biology , biochemistry , amino acid , gene
The well‐characterized enhancement of the cardiac Ca 2+ L‐type current by protein kinase A (PKA) is not observed when the corresponding channel is expressed in Xenopus oocytes, possibly because it is fully phosphorylated in the basal state. However, the activity of the expressed channel is reduced by PKA inhibitors. Using this paradigm as an assay to search for PKA sites relevant to channel modulation, we have found that mutation of serine 1928 of the α 1C subunit to alanine abolishes the modulation of the expressed channel by PKA inhibitors. This effect was independent of the presence of the β subunit. Phosphorylation of serine 1928 of α 1C may mediate the modulatory effect of PKA on the cardiac voltage‐dependent Ca 2+ channel.