Alternative splicing generates a CaM kinase IIbeta isoform in myocardium that targets the sarcoplasmic reticulum through a putative alphaKAP and regulates GAPDH.
We report the isolation of a full length cDNA from cardiac muscle that encodes a approximately 73 kDa calcium/calmodulin (CaM) dependent kinase IIbeta isoform (CaMKIIbeta(C)) that was generated by alternative splicing of the CaMKIIbeta gene. Antipeptide antibodies raised to specific regions of the kinase identified a 73 kDa kinase polypeptide in cardiac SR. Anti-alpha kinase anchoring protein (alphaKAP) antibodies identified a 25 kDa polypeptide in cardiac SR and RT-PCR followed by sequence analysis confirmed the presence of a full length alphaKAP encoding transcript in myocardium. Protein interaction assays revealed that the 73 kDa CaMKIIbeta(C) binds GAPDH to modulate the production of NADH in a Ca2+/CaM dependent reaction. The presence of a CaMKIIbeta isoform that can target the SR presumably via its membrane anchor alphaKAP defines a previously unrecognized Ca2+/CaM regulatory system in myocardium.
Singh
Puneet
P
Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada.
Leddy
John J
JJ
Chatzis
George J
GJ
Salih
Maysoon
M
Tuana
Balwant S
BS
D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000737:chemistry* / Q000235:genetics*; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005091:Exons; D015723:Gene Library; D005982:Glutathione Transferase / Q000378:metabolism; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000096:biosynthesis*; D006801:Humans; D015151:Immunoblotting; D007438:Introns; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000378:metabolism; D009206:Myocardium / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology*; D009243:NAD / Q000378:metabolism; D010455:Peptides / Q000737:chemistry; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014018:Tissue Distribution
D018076:DNA, Complementary; D010455:Peptides; D020033:Protein Isoforms; D009243:NAD; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D005982:Glutathione Transferase; C517658:CAMK2B protein, human; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2; D017871:Calcium-Calmodulin-Dependent Protein Kinases