scholarly journals Proteolytic and chemical dissection of the human erythrocyte glucose transporter

1984 ◽  
Vol 221 (1) ◽  
pp. 179-188 ◽  
Author(s):  
M T Cairns ◽  
D A Elliot ◽  
P R Scudder ◽  
S A Baldwin
Keyword(s):  
Human Erythrocyte ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Diffuse Band ◽  
Cytoplasmic Surface ◽  
Cytoplasmic Face ◽  
Membrane Bound ◽  
Beta Galactosidase

Treatment of the purified, reconstituted, human erythrocyte glucose transporter with trypsin lowered its affinity for cytochalasin B more than 2-fold, and produced two large, membrane-bound fragments. The smaller fragment (apparent Mr 18000) ran as a sharp band on sodium dodecyl sulphate (SDS)/polyacrylamide-gel electrophoresis. When the transporter was photoaffinity labelled with [4-3H]cytochalasin B before tryptic digestion, this fragment became radiolabelled and so probably comprises a part of the cytochalasin B binding site, which is known to lie on the cytoplasmic face of the erythrocyte membrane. In contrast, the larger fragment was not radiolabelled, and ran as a diffuse band on electrophoresis (apparent Mr 23000-42000). It could be converted to a sharper band (apparent Mr 23000) by treatment with endo-beta-galactosidase from Bacteroides fragilis and so probably contains one or more sites at which an oligosaccharide of the poly(N-acetyl-lactosamine) type is attached. Since the transporter bears oligosaccharides only on its extracellular domain, whereas trypsin is known to cleave the protein only at the cytoplasmic surface, this fragment must span the membrane. Cleavage of the intact, endo-beta-galactosidase-treated, photoaffinity-labelled protein at its cysteine residues with 2-nitro-5-thiocyanobenzoic acid yielded a prominent, unlabelled fragment of apparent Mr 38000 and several smaller fragments which stained less intensely on SDS/polyacrylamide gels. Radioactivity was found predominantly in a fragment of apparent Mr 15500. Therefore it appears that the site(s) labelled by [4-3H]cytochalasin B lies within the N-terminal or C-terminal third of the intact polypeptide chain.

Reconstitution of D-glucose transporter from human placental microvillous plasma membranes

1982 ◽  
Vol 242 (3) ◽  
pp. C166-C171 ◽  
Author(s):  
J. M. Bissonnette ◽  
J. A. Black ◽  
K. L. Thornburg ◽  
K. M. Acott ◽  
P. L. Koch
Keyword(s):  
Glucose Uptake ◽  
Plasma Membranes ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Extraction Procedure ◽  
Membrane Vesicles ◽  
Plasma Membrane Vesicles ◽  
Human Trophoblast

Proteins from microvillous plasma membrane vesicles of the maternal surface of human trophoblast were solubilized with octyl beta-D-glucoside. After incorporation of the soluble protein into phospholipid liposomes D-glucose uptake exceeded that of L-glucose. The reconstituted system showed that D-glucose uptake was not sodium dependent and was inhibited by cytochalasin B. Efflux of D-glucose from the proteoliposomes was retarded by cytochalasin B. D-Glucose uptake, but not L-glucose, was proportional to the amount of protein used in the reconstitution procedure. Membrane protein was also solubilized with octylglucoside from vesicles that had been extracted previously by dimethylmaleic anhydride. Proteoliposomes prepared from these latter proteins showed D-glucose uptake threefold greater than that from octylglucoside solubilization alone, but sodium dodecyl sulfate polyacrylamide gel electrophoresis of the extracted protein showed no clear difference between the double extraction procedure and the pattern obtained with the single detergent.

Cytochalasin-B-binding proteins related to glucose transport across the basolateral membrane of the intestinal epithelial cell

1986 ◽  
Vol 85 (1) ◽  
pp. 177-185
Author(s):  
T. Uezato ◽  
M. Fujita
Keyword(s):  
Glucose Transport ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Basolateral Membrane ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Membrane Vesicles ◽  
Intestinal Epithelial ◽  
Similar Extent ◽  
Basolateral Membranes

Basolateral membrane vesicles were isolated from mouse enterocytes. The vesicles showed Na+-independent uptake of D-glucose. The uptake was inhibited by cytochalasin B and phloretin with 50% inhibition at 2.0 microM and 25 microM, respectively. 2-Deoxy-D-glucose inhibited D-glucose transport by 50% at 0.5 M. The basolateral membranes bound 13.5 pmol mg protein-1 of 0.1 microM-cytochalasin B. The effects of various monosaccharides on cytochalasin B binding were examined; the strongest inhibitor was 2-deoxy-D-glucose (20–30%). Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of the basolateral membranes labelled with [3H]cytochalasin B revealed two components with Mr values of 52(+/− 2) and 30(X 10(3)). Phloretin and 2-deoxy-D-glucose inhibited the photo-incorporation of [3H]cytochalasin B into these components. While phloretin inhibited the photolabelling of the two components to a similar extent, 2-deoxy-D-glucose seemed to inhibit preferentially that into the 52 X 10(3) Mr component. The similar sensitivity to 2-deoxy-D-glucose of the photolabelling of the 52 X 10(3) Mr component and of D-glucose transport, together with the fact that dithiothreitol removal increased the incorporation into the 52 X 10(3)Mr component and decreased that into the 30 X 10(3) Mr component, seems to suggest that the 52 X 10(3) Mr component is the major glucose transporter of the basolateral membrane.

scholarly journals Time-dependent association between platelet-bound fibrinogen and the Triton X-100 insoluble cytoskeleton

Blood ◽  
1991 ◽  
Vol 77 (3) ◽  
pp. 508-514 ◽  
Author(s):  
EI Peerschke
Keyword(s):  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Adenosine Diphosphate ◽  
Time Dependent ◽  
Binding Studies ◽  
Fibrinogen Binding ◽  
Human Thrombin ◽  
Membrane Bound ◽  
Independent Association ◽  
Triton X

Abstract Previous studies indicated a correlation between the formation of EDTA- resistant (irreversible) platelet-fibrinogen interactions and platelet cytoskeleton formation. The present study explored the direct association of membrane-bound fibrinogen with the Triton X-100 (Sigma Chemical Co, St Louis, MO) insoluble cytoskeleton of aspirin-treated, gel-filtered platelets, activated but not aggregated with 20 mumol/L adenosine diphosphate (ADP) or 150 mU/mL human thrombin (THR) when bound fibrinogen had become resistant to dissociation by EDTA. Conversion of exogenous 125I-fibrinogen to fibrin was prevented by adding Gly-Pro-Arg and neutralizing THR with hirudin before initiating binding studies. After 60 minutes at 22 degrees C, the cytoskeleton of ADP-treated platelets contained 20% +/- 12% (mean +/- SD, n = 14) of membrane-bound 125I-fibrinogen, representing 10% to 50% of EDTA- resistant fibrinogen binding. The THR-activated cytoskeleton contained 45% +/- 15% of platelet bound fibrinogen, comprising 80% to 100% of EDTA-resistant fibrinogen binding. 125I-fibrinogen was not recovered with platelet cytoskeletons if binding was inhibited by the RGDS peptide, excess unlabeled fibrinogen, or disruption of the glycoprotein (GP) IIb-IIIa complex by EDTA-treatment. Both development of EDTA- resistant fibrinogen binding and fibrinogen association with the cytoskeleton were time dependent and reached maxima 45 to 60 minutes after fibrinogen binding to stimulated platelets. Although a larger cytoskeleton formed after platelet stimulation with thrombin as compared with ADP, no change in cytoskeleton composition was noted with development of EDTA-resistant fibrinogen binding. Examination of platelet cytoskeletons using monoclonal antibodies, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and Western blotting showed the presence of only traces of GP IIb-IIIa in the cytoskeletons of resting platelets, with no detectable increases after platelet activation or development of EDTA-resistant fibrinogen binding. These data suggest that GP IIb-IIIa-mediated fibrinogen binding to activated platelets is accompanied by time-dependent alterations in platelet- fibrinogen interactions leading to the GP IIb-IIIa independent association between bound fibrinogen and the platelet cytoskeleton.

scholarly journals Human erythrocyte antigens: II. The In(Lu) gene regulates expression of an antigen on an 80-kilodalton protein of human erythrocytes

Blood ◽  
1984 ◽  
Vol 64 (3) ◽  
pp. 599-606 ◽  
Author(s):  
MJ Telen ◽  
TJ Palker ◽  
BF Haynes
Keyword(s):  
Monoclonal Antibody ◽  
Western Blot ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein A ◽  
Sodium Dodecyl ◽  
Two Dimensions ◽  
Antigen Activity

Abstract We have previously shown that a murine monoclonal antibody (A3D8) identifies a human erythrocyte protein antigen whose expression is regulated by the Lutheran inhibitor [In(Lu)] gene. In the present study, we demonstrated by immunoprecipitation and Western blot techniques that the antigen defined by A3D8 was on an 80-kD erythrocyte membrane protein. A second 170-kD protein was coprecipitated with the 80-kD protein but failed to show antigen activity by Western blot analysis. The 170-kD protein, when analyzed by sodium dodecyl sulfate- polyacrylamide gel electrophoresis in two dimensions, was composed of 50- and 30-kD disulfide-linked subunits. In(Lu) Lu[a-b-) erythrocytes differed from Lu(a+b+) or Lu(a-b+) erythrocytes in that In(Lu) deoxycholate erythrocyte membrane extracts contained trace amounts of immunoprecipitable 80-kD protein compared with detergent-solubilized erythrocyte membrane extracts prepared from Lu(a+b+) or Lu(a-b+) subjects.

scholarly journals Structural relationships between human erythrocyte sialoglycoproteins β and γ and abnormal sialoglycoproteins found in certain rare human erythrocyte variants lacking the Gerbich blood-group antigen(s)

1987 ◽  
Vol 244 (1) ◽  
pp. 123-128 ◽  
Author(s):  
M E Reid ◽  
D J Anstee ◽  
M J A Tanner ◽  
K Ridgwell ◽  
G T Nurse
Keyword(s):  
Blood Group ◽  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Blood Group Antigen ◽  
Human Erythrocyte Membrane ◽  
Diffuse Band ◽  
Structural Relationships ◽  
Normal Erythrocyte

The human erythrocyte membrane sialoglycoproteins beta and gamma are important for the maintenance of the discoid shape of the normal erythrocyte. In this paper we show that the human erythrocyte sialoglycoproteins beta and gamma (hereafter called beta and gamma) are structurally related. Rabbit antisera produced against purified beta and beta 1 and rendered specific to the cytoplasmic portion of these proteins also react with the cytoplasmic portion of gamma. Some human anti-Gerbich (Ge) sera react with the extracellular portion of both beta and gamma. This reactivity is shown to be directed towards a common epitope on beta and gamma. However, most anti-Ge sera do not react with beta, but react with an extracellular epitope only present on gamma. All individuals who lack the Ge antigens lack beta and gamma. In some cases abnormal sialoglycoproteins are present in the erythrocytes, and these are shown to be structurally related to beta and gamma. Rabbit antisera raised against the purified abnormal sialoglycoprotein from a Ge-negative erythrocyte type reacted with the cytoplasmic portion of both beta and gamma. Unlike normal beta and gamma, the abnormal sialoglycoproteins found in Ge-negative erythrocytes migrate as a diffuse band on SDS/polyacrylamide-gel electrophoresis. Studies using endoglycosidases suggest that the diffuse nature of these bands results from carbohydrate heterogeneity and that the abnormal sialoglycoproteins contain N-glycosidically linked oligosaccharides with repeating lactosamine units. Such polylactosamine chains are not present on normal beta or gamma.

scholarly journals Glycation of the human erythrocyte glucose transporter in vitro and its functional consequences

1990 ◽  
Vol 268 (3) ◽  
pp. 661-667 ◽  
Author(s):  
P J Bilan ◽  
A Klip
Keyword(s):  
Erythrocyte Membrane ◽  
Human Erythrocyte ◽  
Glucose Transporter ◽  
Cytochalasin B ◽  
Competitive Inhibitor ◽  
Human Erythrocyte Membrane ◽  
Functional Consequences ◽  
High Concentrations ◽  
Erythrocyte Membrane Proteins

Glycation of human erythrocyte membrane proteins was induced by incubation in vitro with high concentrations (80 mM or 200 mM) of D-glucose for 3 or 6 days. The extent of glycation was quantified from the covalent incorporation of 3H by reduction of the glucose glycation products with NaB3H4. For membranes incubated for 3 days with 80 mM-D-glucose, glycation in vitro of Band 4.5 (containing the glucose transporter) was equivalent to 0.11 mol of glucose/mol of glucose transporter, compared with 3H labelling in 3-day-incubated control membranes of 0.055 mol of glucose/mol of glucose transporter. In membranes incubated for 6 days with 200 mM-D-glucose, glycation increased to 0.21 mol of glucose/mol of glucose transporter, whereas the controls without glucose had 0.11 mol of glucose/mol of glucose transporter. Glycation in vitro was accompanied by a fall in the Bmax of binding of [3H]cytochalasin B (a competitive inhibitor of glucose transport), without any change in the binding affinity. The data suggest that glycated glucose transporters have decreased ability to bind cytochalasin B. It is proposed that glycation can alter glucose transporter activity.

scholarly journals Specific and azurophilic granules from rabbit polymorphonuclear leukocytes. I. Isolation and characterization of membrane and content subfractions.

1983 ◽  
Vol 96 (4) ◽  
pp. 1030-1039 ◽  
Author(s):  
W J Brown ◽  
W A Shannon ◽  
W J Snell
Keyword(s):  
Membrane Proteins ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Protein Composition ◽  
Granule Protein ◽  
Isolation And Characterization ◽  
Cytoplasmic Face ◽  
Sds Page ◽  
Granule Membrane ◽  
Granule Membrane Proteins

The specific and azurophilic granules of rabbit polymorphonuclear heterophils (PMNs) have been isolated and fractionated into membrane and extractable subfractions. Analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) revealed several features of the protein composition of the two granules: (a) Whereas each type of granule had 40-60 proteins separable on one-dimensional gradient gels, few of the proteins were common to both granules. (b) The proteins of the extractable fractions (which comprised approximately 98% of the total granule protein) of each granule were distinct from the proteins of the membrane fractions (which comprised approximately 2% of the total granule protein). (c) The extractable proteins co-migrated with those collected from the medium of ionophore-treated, degranulating PMNs and therefore were defined as content proteins. These results were confirmed by radiolabeling studies. Lactoperoxidase-catalyzed iodination of intact granules did not label the content proteins but did label proteins that co-migrated with major granule membrane proteins. Moreover, disruption of the granules before iodination led to labeling of both content and membrane proteins. We conclude that the membranes of specific and azurophilic granules, which arise from different faces of the Golgi complex, are composed of unique sets of membrane proteins some of which are exposed on the cytoplasmic face of the granules.

scholarly journals Soluble stem cell factor in human serum

Blood ◽  
1993 ◽  
Vol 81 (3) ◽  
pp. 656-660 ◽  
Author(s):  
KE Langley ◽  
LG Bennett ◽  
J Wypych ◽  
SA Yancik ◽  
XD Liu ◽  
...  
Keyword(s):  
Stem Cell ◽  
Human Serum ◽  
Stem Cell Factor ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Immunoaffinity Chromatography ◽  
Soluble Form ◽  
Enzyme Linked Immunosorbent Assay ◽  
Functional Importance ◽  
Membrane Bound

Stem cell factor (SCF) is a recently described factor active in the early stages of hematopoiesis. It can exist in membrane-bound form and in proteolytically released soluble form. The levels and nature of SCF in human serum are described. As determined by an enzyme-linked immunosorbent assay performed for 257 samples, SCF level in serum averaged 3.3 +/- 1.1 ng/mL. The serum SCF was partially purified by immunoaffinity chromatography and analyzed by glycosidase treatments in conjunction with sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting. The results show that the SCF has N- linked and O-linked carbohydrate and corresponds to the soluble form, at or about 165 amino acids in length. The findings suggest functional importance for soluble SCF in humans.

Insertions of transposon Tn5 into ribosomal protein PNA polymerase operons

1982 ◽  
Vol 152 (3) ◽  
pp. 1022-1032
Author(s):  
I Hui ◽  
K Maltman ◽  
R Little ◽  
S Hastrup ◽  
M Johnsen ◽  
...  
Keyword(s):  
Ribosomal Protein ◽  
Gel Electrophoresis ◽  
Polyacrylamide Gel Electrophoresis ◽  
Sodium Dodecyl ◽  
Polyacrylamide Gel ◽  
Lacz Gene ◽  
Ribosomal Protein Genes ◽  
Lacz Gene Fusions ◽  
Protein Transcription ◽  
Beta Galactosidase

The genetic organization and interrelationships between the two ribosomal protein transcription units (the L11 and L10 operons) from near 89 min on the Escherichia coli chromosome were studied by using insertional mutations generated by the kanamycin-resistant transposable element Tn5. The polar effects of Tn5 insertions on the expression of the L11, L1, L10, and L12 ribosomal protein genes and the beta RNA polymerase subunit gene were examined (i) by the level of beta-galactosidase activity generated from L10-lacZ and beta-lacZ gene fusions, (ii) by direct sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the proteins specified by plasmid ribosomal protein genes in UV-irradiated maxicells, and (iii) by urea-polyacrylamide gel electrophoresis of plasmid- and chromosome-specified L12 protein. The results confirmed the organization of these genes into two transcription units as follows: PL11, rplK (L11), rplA (L1), PL10, rplJ (L10), rplL (L12), rpoB (beta). . .; they also localized the position of the PL10 promoter within an 80-nucleotide region near the end of the L1 gene. The results also support the idea that the translational regulatory proteins for the L11 and L10 operons are L1 and L10, respectively, and that the expression of the L12 gene is closely linked to L10 gene expression.

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