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

Abstract

Senescent cell antigen, a polypeptide that appears on the surface of senescent and damaged cells, has been shown to be derived from band 3. In the present study, 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 transport in human erythrocytes, the glucose transport carrier was isolated by affinity chromatography on cytochalasin 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 Mr =60,000 when analyzed by NaDod-SO4/PAGE. 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. In addition, 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 Mr =41,000 cytoplasmic segment of band 3 that contains the amino terminus could not be demonstrated. Thus, glucose transporter appears to be part of or derived from band 3, and to share substantial peptide homology with senescent cell antigen.

Alzheimer’s Disease and Cellular Aging: Membrane-Related Events as Clues to Primary Mechanisms

“…The absence of reduction of ouabain binding to brain capillaries [94] presents an argument against nonspecific degeneration but rather for involvement of specific mem brane proteins in Alzheimer's disease. Presently available cDNA data do not indi cate a homology between the erythrocyte an ion and glucose transport proteins [82,95], However, not only the aberrant glucose transport characteristics of red blood cells containing altered band 3 molecules [41,42,75], but also the marked glucose hypometabolism in caudate and putamen of patients with neuroacanthocytosis [96], a disease in which erythrocyte band 3 is clearly altered [42], confirm earlier immunological and structural indications for an intimate func tional relationship between these two mem brane proteins [97], In preliminary studies, we found an increase in cytochalasin B bind ing to erythrocytes from an Alzheimer pa tient, which also showed an increased amount of cell-bound IgG and altered sulfate transport characteristics (data not shown). These findings warrant further investiga tions on function and structure of the glu cose transporter in the central nervous sys tem and in erythrocytes (and other periph eral cells) of Alzheimer patients.…”

Aging of Cell Membrane Molecules Leads to Appearance of an Aging Antigen and Removal of Senescent Cells

“…The glucose transport pro tein, which is the larger of the two molecules, apears to include all of the transmembrane region of band 3, whereas senescent cell anti gen appears to contain only approximately a third of that region [50,52]. Thus, the glucose transporter that supplies energy to cells and senescent cell antigen that terminates the life of cells appear to be related polypeptides based on immunologic and structural data.…”

Density‐related changes of potassium (86Rb) uptake by amphibian endothelial cells

“…As a consequence, the enhancement of Na + /K+ -ATPase, which seems to be closely related to growth stimulation (Saishu et al, 1985), is supposed to result from either an unmasking or a n activation of the enzyme, probably by a n increased Na' influx as occurs, e.g., through amiloride-sensitive channels (Levine et al, 1965;Fine et al, 1985) or furosemidesensitive routes (Paris and Pouyssegur, 1986). Thus sodium influx could act as a trigger for the activation of the Na + / K i -ATPase (Leister et al, 1985;Frantz et al, 1981), which in turn, by its association with cytoskeletal elements (Geny et al, 1982;Balaban and Bader, 1984;Kay, 1985) and by concommittant shifts in pH and ionic composition, may stimulate DNA synthesis (Pouyssegur et al, 1985) by one or another mechanism suggested by Racker (19761, Kajstura andKorohoda (1982), or Bereiter-Hahn (1988). The changes observed when cultures become confluent could be related to restriction of cellular motility; the subsequent decrease of Na +/K+-ATPase activity corresponds well with the activity decrease of this enzyme in contact-inhibited cells (Lelievre et al, 1971;Elligsen et al, 1976).…”