Title : The high-affinity sulfonylurea
receptor : distribution, glycosylation, purification, and immunoprecipitation of two forms from endocrine and neuroendocrine cell lines
Abstract :
- The high-affinity sulfonylurea receptor , a novel member of the ATP-binding cassette superfamily, is one component of the ATP-sensitive K+ channel
- The protein is critical for regulation of insulin secretion from pancreatic beta-cells, and mutations in the receptor have been linked to familial hyperinsulinemia, a disorder characterized by unregulated insulin release despite severe hypoglycemia
- The sulfonylurea receptor is present in membranes from a number of endocrine and neuroendocrine cell lines, including HIT-T15, RINm5f, alpha TC-6, AtT-20, and GH3 cells
- Two forms of the receptor are present in RINm5f and alpha TC-6 cells, with apparent SDS gel molecular masses of 140 and 150 kDa
- The two forms have equally high affinity, KD approximately 3 nM, for an iodinated derivative of glyburide, an anti-diabetic sulfonylurea
- The receptor is a glycoprotein ; treatment of RINm5f or alpha TC-6 cells with tunicamycin reduces the 140 and 150 kDa species to a single approximately 137 kDa protein
- The 140 and 150 kDa receptors bind differentially to concanavalin A and wheat germ agglutinin , and lectin-affinity chromatography is ideal for the initial stages of receptor purification
- After lectin-affinity chromatography, the same methods can be applied for purifying the 150 kDa form as for the 140 kDa receptor
- A transiently expressed receptor with a histidine-tagged carboxy-terminus was purified by Ni-agarose chromatography, and this variant was used to demonstrate that the 140 kDa polypeptide is full length
- Anti-peptide antibodies directed against the amino-terminus of the receptor and antibodies against the nucleotide binding folds immunoprecipitate both receptor forms
- The results indicate the 140 and 150 kDa receptors are differentially glycosylated forms of the same polypeptide chain
Output (sent_index, trigger,
protein,
sugar,
site):
- 11. glycosylated, , receptors, -, -
- 6. glycoprotein, , glycoprotein, -, -
- 6. glycoprotein, , receptor, -, -
Output(Part-Of) (sent_index,
protein,
site):
*Output_Site_Fusion* (sent_index,
protein,
sugar,
site):