Association of stomatin (band 7.2b) with Glut1 glucose transporter.
Employing a monoclonal antibody directed against the C-terminal peptide of glucose transporter molecule 1 (Glut1), we identified a approximately 30-kDa polypeptide which coimmunoprecipitated with Glut1 from sample of human red blood cells (RBC) membranes. The approximately 30-kDa polypeptide reacted with an antibody directed against stomatin, an integral plasma membrane protein which is also present at a high abundance in the human RBC plasma membrane. Likewise, employing anti-stomatin antibody, we found that Glut1 coimmunoprecipitated with stomatin from samples of RBC membranes. However, neither band 3, which is the most abundant integral membrane protein in the RBC, nor actin coimmunoprecipitated with Glut1, indicating a specific interaction between Glut1 and stomatin. Similar to the results obtained in the RBC, Glut1 and stomatin immunoprecipitated with each other in lysates of Clone 9 cells, a rat liver cell line in which Glut1 is expressed at approximately 1/200 the level present in RBC. Employing conditions that resulted in immunoprecipitation of approximately 10% of Glut1 in RBC membranes led to a approximately 3% coimmunoprecipitation of stomatin. A mixed population of Clone 9 cells stably transfected with a plasmid overexpressing the mouse stomatin exhibited 30 +/- 3% reduction in the basal rate of glucose transport compared to control cells or cells stably transfected with the empty vector. The above results suggest that stomatin is closely associated with Glut1 in the plasma membrane and that overexpression of stomatin results in a depression in the basal rate of glucose transport.
Zhang
J Z
JZ
Departments of Medicine and of Physiology and Biophysics, Case Western Reserve University, Cleveland, Ohio, 44106-4951, USA.
Hayashi
H
H
Ebina
Y
Y
Prohaska
R
R
Ismail-Beigi
F
F
D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D001693:Biological Transport, Active; D001798:Blood Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D004910:Erythrocyte Membrane / Q000737:chemistry; D005947:Glucose / Q000378:metabolism; D051272:Glucose Transporter Type 1; D006801:Humans; D066298:In Vitro Techniques; D008565:Membrane Proteins; D051379:Mice; D009004:Monosaccharide Transport Proteins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D011233:Precipitin Tests; D051381:Rats
D000911:Antibodies, Monoclonal; D001798:Blood Proteins; D017931:DNA Primers; C488964:Stom protein, mouse; D051272:Glucose Transporter Type 1; D008565:Membrane Proteins; D009004:Monosaccharide Transport Proteins; C495677:SLC2A1 protein, human; C036860:STOM protein, human; C495678:Slc2a1 protein, mouse; C495679:Slc2a1 protein, rat; D005947:Glucose