Glucose transport protein is structurally and immunologically related to band 3 and senescent cell antigen.

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Abstract
Senescent cell antigen, a polypeptide that appears on the surface of senesecent and damaged cells, was shown to be derived from band 3. The relationship between the as yet unidentified glucose transporter and senescent cell antigen is examined. Since cytochalasin B is a specific and potent competitive inhibitor of glucose B-Sepharose 4B columns and eluted with D-glucose. This purification procedure is both a method of isolation and a functional assay for the glucose transporter. Purified glucose transporter gave a sharp, single band at MW .simeq. 60,000 when analyzed by NaDodSO4/PAGE [sodium dodecyl sulfate/polyacrylamide gel electrophoresis]. Glucose transporter was identified in erythrocyte membranes by the immunoblotting technique, using both antibodies raised against purified glucose transporter and antiidiotypic antibodies. Two-dimensional peptide mapping revealed substantial peptide homology between glucose transporter and senescent cell antigen. The glucose transporter shared peptide homology with band 3 and its defined proteolytic fragments located toward the carboxyl terminus of band 3. Peptide homology between glucose transporter and the MW .simeq. 41,000 cytoplasmic segment of band 3 that contains the amino terminus could not be demonstrated. Glucose transporter appears to be part of or derived from band 3, and to share substantial peptide homology with senescent cell antigen.