Hydrophobic interactions stabilize the basigin-MCT1 complex.

Previous reports demonstrated that monocarboxylate transporter-1 (MCT1) interacts with Basigin. It was hypothesized that the two proteins interact via the transmembrane domain of Basigin, specifically through the glutamate residue within the domain. We therefore sought to test this hypothesis and determine which amino acids of the Basigin protein are necessary for the interaction with MCT1. Probes consisting of the full-length putative transmembrane domain, as well as small regions of the domain, were generated for use in ELISA binding assays using endogenous mouse MCT1. Site directed mutagenesis of candidate residues was performed and probes were generated for ELISA analyses to determine the specific residues involved. The data suggest that hydrophobic residues at the N- and C-termini of the putative transmembrane domain of Basigin interact with MCT1, but the glutamate plays no role. The previously proposed hypothesis is partially correct, in that the putative transmembrane domain of Basigin does interact with MCT1.