Determination of the molecular mass of the native beta-cell sulfonylurea receptor.

Journal article

In the present study we have determined the molecular mass of the beta-cell sulfonylurea receptor in its native form by two different experimental approaches; gel filtration chromatography and radiation inactivation analysis. We first confirmed that the denatured photolabelled MIN6 beta-cell receptor had a molecular size of 141 +/- 2 kDa (mean +/- S.E., n = 8). Under non-denaturing conditions, using gel filtration chromatography, apparent molecular masses of 166 +/- 1 kDa (mean +/- S.E., n = 3) and 182 +/- 5 kDa (mean +/- S.E., n = 4) were determined for the photoaffinity-labelled and unlabelled sulfonylurea receptor, respectively. We conclude that in the solubilized state the receptor exists as a monomer. Radiation inactivation analysis indicated that the receptor has a target size of 250 +/- 30 kDa (mean +/- S.E., n = 7). This value for the molecular mass is larger than that obtained from SDS-PAGE following photolabelling of the receptor (141 kDa) suggesting that the beta-cell sulfonylurea receptor is composed of more than one subunit in the native membrane.

Authors: Skeer, J; Dégano, P; Coles, B; Potier, M; Ashcroft, F

• Publication status: Published
• Journal: FEBS letters
• Volume: 338
• Issue: 1
• Pages: 98-102
• Publication date: 1994-01-01
• DOI: 10.1016/0014-5793(94)80124-x
• EISSN: 1873-3468
• ISSN: 0014-5793
• Language: English
• Keywords: Chromatography, Gel; ATP-Binding Cassette Transporters; Islets of Langerhans; Cells, Cultured; Molecular Weight; Affinity Labels; Cell Membrane; Potassium Channels, Inwardly Rectifying; Potassium Channels; Electrophoresis, Polyacrylamide Gel; Receptors, Drug