Characterization of a Novel Porcine EndothelinBReceptor Splice Variant
- Departments of 1Renal Pharmacology (P.N., H.-L.W., D.Y.) and 2Molecular Biology (A.G., N.E.), SmithKline Beecham Pharmaceuticals, King of Prussia, Pennsylvania
Abstract
Screening of porcine cerebellum cDNA library with porcine endothelinB (ETB) receptor cDNA revealed a novel ETB receptor cDNA that is distinctly different from the wild-type ETB receptor in length and the amino acid sequence at the C-terminal end. This sequence appears to represent alternate splicing of the carboxy terminal end of ETBreceptor, resulting in a polypeptide of 429 amino acids in length, which is 14 amino acids shorter than the wild-type porcine ETB receptor. Characterization of the wild-type and alternately spliced ETB receptors expressed in COS cells revealed that both receptors displayed very similar binding [apparent dissociation constant (Kd) and maximum binding (Bmax) for 125I-ET-1 were 71 pM and 1.6 pmol/mg protein for wild-type and 81 pM and 1.2 pmol/mg protein for splice variant ETB receptors] as well as functional properties. These data suggest that the differences in the amino acids at the C-terminal end had no effect on binding or functional coupling of these alternately spliced ETBreceptors.
Footnotes
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Send reprint requests to: Ponnal Nambi, Ph.D., Cardiovascular Sciences, DuPont Pharmaceuticals Company, Experimental Station, E 400/3237, Wilmington, DE 19880-0400.
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↵1 Present address: Cardiovascular Sciences, DuPont Pharmaceuticals Company, Experimental Station, E 400/3237, Wilmington, DE 19880-0400.
- Abbreviations:
- ET
- endothelin
- S6c
- sarafotoxin 6c
- ETB-SVR
- ETB splice variant receptor
- bp
- base pair
- PDBu
- phorbol-12,13-dibutyrate
- TM
- transmembrane
- GRK
- G protein-coupled receptor kinases
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- Received December 22, 1998.
- Accepted August 11, 1999.
- The American Society for Pharmacology and Experimental Therapeutics
