Molecular cloning and functional expression of the cardiac sarcolemmal Na(+)-Ca2+ exchanger.
The Na(+)-Ca2+ exchanger of the cardiac sarcolemma can rapidly transport Ca2+ during excitation-contraction coupling. To begin molecular studies of this transporter, polyclonal antibodies were used to identify a complementary DNA (cDNA) clone encoding the Na(+)-Ca2+ exchanger protein. The cDNA hybridizes with a 7-kilobase RNA on a Northern blot and has an open reading frame of 970 amino acids. Hydropathy analysis suggests that the protein has multiple transmembrane helices, and a small region of the sequence is similar to that of the Na(+)- and K(+)-dependent adenosine triphosphatase. Polyclonal antibodies to a synthetic peptide from the deduced amino acid sequence react with sarcolemmal proteins of 70, 120, and 160 kilodaltons on immunoblots. RNA, synthesized from the cDNA clone, induces expression of Na(+)-Ca2+ exchange activity when injected into Xenopus oocytes.
Department of Medicine, UCLA School of Medicine 90024-1760.
D A
DA
Nicoll
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Longoni
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Philipson
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D015342:DNA Probes; D004285:Dogs; D015870:Gene Expression; D006031:Glycosylation; D015151:Immunoblotting; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009206:Myocardium / Q000737:chemistry*; D009693:Nucleic Acid Hybridization; D012313:RNA / Q000235:genetics; D018075:RNA, Complementary; D012508:Sarcolemma / Q000737:chemistry*; D019831:Sodium-Calcium Exchanger
D002352:Carrier Proteins; D015342:DNA Probes; D018075:RNA, Complementary; D019831:Sodium-Calcium Exchanger; D012313:RNA; D000255:Adenosine Triphosphate; D004247:DNA