Characterization of antisera to a synthetic carboxyl-terminal peptide of the glucose transporter protein

• Published in: The Journal of biological chemistry Vol. 263; no. 1; pp. 398 - 403
• Main Authors: Haspel, H C, Rosenfeld, M G, Rosen, O M
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 05.01.1988; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Analytical, structural and metabolic biochemistry; Antigen-Antibody Complex; Binding and carrier proteins; Biological and medical sciences; Erythrocyte Membrane - metabolism; Fundamental and applied biological sciences. Psychology; Humans; Immune Sera; Kinetics; Monosaccharide Transport Proteins - blood; Monosaccharide Transport Proteins - immunology; Peptides - immunology; Protein Conformation; Proteins; Human; Antiserum; Radioimmunoassay; Plasma membrane; Red blood cell; Immunoblotting assay; Permeabilizing; Glucose; Immunofluorescence; Localization; Carrier protein; Aminoacid sequence
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(19)57406-3

Peptides corresponding to amino acid residues 1-12 of the amino terminal and 480-492 of the carboxyl terminal of the deduced sequence of the glucose transporter were synthesized and used to produce site-specific polyclonal antipeptide sera. In a solid-phase radioimmunoassay, antiserum to the carboxyl terminal recognizes peptide 480-492 and purified human erythrocyte glucose transporter, but not peptide 1-12. Antiserum to the amino terminal recognizes peptide 1-12 but neither peptide 480-492 nor the erythrocyte transporter. The antiserum to the carboxyl terminal specifically immunoblots the Mr 55,000 glucose transporter in erythrocyte membranes and the purified erythrocyte transporter. It also recognizes a Mr 40,000-60,000 polypeptide in membranes of cells derived from different mammalian species and tissues including insulin-sensitive rat adipocytes as well as a Mr 20,000 tryptic fragment of the transporter which contains the site for photolabeling by cytochalasin B. Antiserum to the carboxyl terminal of the transporter binds specifically to leaky erythrocyte membranes but not to intact erythrocytes. This binding is saturable and competitively inhibited by peptide 480-492. Using immunofluorescence microscopy, this antiserum detects glucose transporter protein in permeabilized erythrocytes, but not in intact erythrocytes. These studies provide immunochemical evidence in support of the predicted cytoplasmic orientation of the carboxyl terminus of the glucose transporter, allow us to suggest a spatial relationship of the cytochalasin B binding site to the carboxyl terminal of the glucose transporter and suggest that antisera directed to the carboxyl terminal domain of the protein may be useful for the immunocytochemical localization of the glucose transporter.