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Analyses of the co‐localization of cellubrevin and the GLUT4 glucose transporter in rat and human insulin‐responsive tissues
Author(s) -
Aledo J.Carlos,
Hajduch Eric,
Darakhshan Froogh,
Hundal Harinder S
Publication year - 1996
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(96)01044-7
Subject(s) - glut4 , skeletal muscle , biology , intracellular , glucose transporter , vesicle , biochemistry , microbiology and biotechnology , insulin , membrane , endocrinology
We have investigated the subcellular distribution and association of cellubrevin, a low molecular weight protein implicated in the process of membrane fusion, with intracellular membranes containing the insulin‐sensitive GLUT4 glucose transporter from rat adipocytes, rat skeletal muscle and human skeletal muscle. SDS‐PAGE and immunoblot analyses of subcellular fractions of adipocytes and skeletal muscle indicated a positive correlation between the distribution of GLUT4 and cellubrevin in intracellular membrane fractions tested from all tissues. The identity of the polypeptide reacting with antiserum against cellubrevin was further confirmed on the basis of its susceptibility to proteolysis by tetanus toxin. Immunoisolation of GLUT4‐containing vesicles from a microsomal fraction enriched with GLUT4 and cellubrevin revealed that cellubrevin could be coprecipitated with GLUT4 vesicles from adipocytes. In contrast, intracellular GLUT4 vesicles isolated from both rat and human skeletal muscle were devoid of any detectable immunoreactivity towards cellubrevin. The observation that cellubrevin does not colocalise with intracellular GLUT4 in skeletal muscle from two different species, rat and human, would strongly suggest that it is unlikely to participate in the insulininduced delivery of GLUT4 to the cell surface in skeletal muscle.