Functional expression of human renal Na+/Ca2+ exchanger in insect cells.
The cDNA coding for the human renal isoform of the Na+/Ca2+ exchanger was cloned from a human embryonic kidney cell line (HEK 293) using a polymerase chain reaction strategy. It was found by sequence analysis that the cDNA encoded for a human kidney isoform of the Na+/Ca2+ exchanger. The kidney isoform is nearly identical to the human cardiac Na+/Ca2+ exchanger except for a segment of amino acids within the predicted cytoplasmic loop region of the molecule. Within this region, the kidney isoform contains a deletion of 36 amino acids, as well as a segment of 33 amino acids that is only 33% identical to the equivalent region of the cardiac exchanger. The cDNA was then tested for function by expression in insect cells. We constructed a recombinant baculovirus containing renal Na+/Ca2+ exchanger cDNA under control of the polyhedrin promoter. High levels of expression and Na+/Ca2+ exchange activity were found in Sf9 insect cells infected with the recombinant virus. Our results indicate that human kidney expresses a functional and alternatively spliced variant of the human cardiac Na+/Ca2+ exchanger.
Loo
T W
TW
Department of Medicine, and Biochemistry, University of Toronto, Ontario, Canada.
Clarke
D M
DM
D000595:Amino Acid Sequence; D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D001483:Base Sequence; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary; D005822:Genetic Vectors; D006801:Humans; D007313:Insecta / Q000166:cytology; D007536:Isomerism; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D015335:Molecular Probes; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D019831:Sodium-Calcium Exchanger
D002352:Carrier Proteins; D018076:DNA, Complementary; D015335:Molecular Probes; D019831:Sodium-Calcium Exchanger