Effect of Ca2+ on protein kinase A-mediated phosphorylation of a specific serine residue in an expressed peptide containing the Ca2+-regulatory domain of scallop muscle Na+/Ca2+ exchanger.
Sequencing of the scallop muscle Na+/Ca2+ exchanger revealed three consensus sequences for phosphorylation by PK-A in the large cytoplasmic loop (R(363)KLTG, R(379)RASV, and R(618)RGSV). Site-directed mutagenesis of the expressed Glu(384)-Ser(713) segment of the f loop identified Ser(621)as a residue phosphorylated by PK-A. The R(618)RGSV sequence is located at the junction of the mutually exclusive exon and exon 9, a site where many alternatively spliced variants of vertebrate NCX1 and NCX3 are generated. Phosphorylation of Ser(621) by PK-A in the isolated Glu(384)-Ser(713) peptide was blocked under conditions where Ca2+ was bound.
Ryan
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Department of Physiology and Cardiovascular Research Laboratories, University of California, Los Angeles, School of Medicine, Los Angeles, California 90095-1760, USA.
Shaw
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Hardwicke
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D017398:Alternative Splicing; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002942:Circular Dichroism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D005091:Exons; D008974:Mollusca; D009132:Muscles / Q000378:metabolism*; D010766:Phosphorylation; D017433:Protein Structure, Secondary; D012694:Serine / Q000378:metabolism*; D019831:Sodium-Calcium Exchanger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D019831:Sodium-Calcium Exchanger; D012694:Serine; D017868:Cyclic AMP-Dependent Protein Kinases; D002118:Calcium