Rapid endocytosis and recycling of wheat germ agglutinin binding sites on CHO cells: Evidence for two compartments in a nondegradative pathway

1990 ◽  
Vol 144 (1) ◽  
pp. 52-61 ◽  
Author(s):  
Thomas J. Raub ◽  
Mary Jo Koroly ◽  
R. Michael Roberts
Keyword(s):  
Cho Cells ◽  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ

scholarly journals Compartmentalization of intracellular membrane glycocomponents is revealed by fracture-label.

1984 ◽  
Vol 98 (1) ◽  
pp. 29-34 ◽  
Author(s):  
M R Torrisi ◽  
P Pinto da Silva
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Secretory Granules ◽  
The Other ◽  
Rat Tissues ◽  
Intracellular Membrane ◽  
Definition Of

We used thin-section fracture-label to determine the distribution of wheat-germ agglutinin binding sites in intracellular membranes of secretory and nonsecretory rat tissues as well as in human leukocytes. In all cases, analysis of the distribution of wheat germ agglutinin led to the definition of two endomembrane compartments: one, characterized by absence of the label, includes the membranes of mitochondria and peroxisomes as well as those of the endoplasmic reticulum and nuclear envelope; the other, strongly labeled, comprises the membrane of lysosomes, phagocytic vacuoles, and secretory granules, as well as the plasma membrane. The Golgi apparatus was weakly labeled in all studied tissues.

Wheat germ agglutinin binding sites in the organ of Corti as revealed by lectin-gold labeling

1987 ◽  
Vol 27 (3) ◽  
pp. 239-244 ◽  
Author(s):  
Masayoshi Tachibana ◽  
Hiroyuki Morioka ◽  
Mitsuo Machino ◽  
Masaki Yoshimatsu ◽  
Osamu Mizukoshi
Keyword(s):  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Organ Of Corti

scholarly journals Expression of 5′Nucleotidase Activity and Wheat-Germ Agglutinin Binding Sites in Mononuclear Phagocytes From Bone Marrow Cultures

1985 ◽  
Vol 37 (3) ◽  
pp. 263-277 ◽  
Author(s):  
R. de Water ◽  
J.W.M. van der Meer ◽  
J.M. van't Noordende ◽  
J.J.M. Onderwater ◽  
J.S. van de Gevel ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Mononuclear Phagocytes ◽  
Nucleotidase Activity ◽  
Bone Marrow Cultures ◽  
Marrow Cultures

scholarly journals Partial purification and characterization of oestrogen receptors in subfractions of hepatocyte plasma membranes

1980 ◽  
Vol 191 (3) ◽  
pp. 743-760 ◽  
Author(s):  
Richard J. Pietras ◽  
Clara M. Szego
Keyword(s):  
Plasma Membrane ◽  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Plasma Membranes ◽  
Specific Binding ◽  
Low Density ◽  
Marker Enzymes ◽  
Low Density Plasma ◽  
Density Plasma

To assess the subcellular distribution of oestrogen-binding components in their native state, plasma membrane and other cell fractions were prepared from hepatocytes in the absence of [3H]oestradiol-17β. Cells from livers of ovariectomized rats were disrupted, with submaximal homogenization in buffered isotonic sucrose with CaCl2 and proteinase inhibitor, and fractionated by using isotonic media. Fractions were characterized by determinations of enzyme activities, biochemical constituents and ligand binding. Specific binding of 2nm-[3H]oestradiol-17β to intact cells and their fractions was detemined after equilibration for 1.5h at 4°C. More than 92% of the radioactivity from representative preparations was verified as authentic oestradiol by thin-layer chromatography. Activities of plasma-membrane marker enzymes as well as binding sites for oestrogen and for wheat germ agglutinin were present principally in particulate fractions, rather than in 105000g-supernatant fractions. However, by using alternative homogenization procedures (i.e. hypotonic media), known to fragment and strip structural components, oestradiol-binding sites and activities of plasma-membrane marker enzymes were distributed predominantly into cytosol. By using the more conservative procedures, plasma membranes of low (ρ=1.13–1.16) and high (ρ=1.16–1.18) density were purified from crude nuclear fractions. A second low-density subfraction of plasma membrane was prepared from microsome-rich fractions. Activities of plasma-membrane marker enzymes were enriched to about 28 and four times that of the homogenate in plasma membranes of low and high density respectively. Binding sites for wheat germ agglutinin and oestradiol were concentrated in low-density plasma membranes to 46–63 times that of the homogenate. Specific binding of oestrogen in low-density plasma membranes purified from crude nuclei was saturable, with an apparent association constant of 3.5nm. At saturation, such oestradiol receptors corresponded to 526fmol/mg of membrane protein. A Hill plot showed a moderate degree of positive co-operativity in the interaction of hormone with plasma membranes. Specific binding of [3H]oestradiol-17β was reduced by a 200-fold molar excess of unlabelled oestradiol-17β, oestriol or diethylstilbestrol, but not by oestradiol-17α, cortisol, testosterone or progesterone. Binding was also blocked by prior exposure of membranes to trypsin or to 60°C, but remained essentially undiminished by extraction of membranes with either hypotonic or high-salt buffers. Extraction with 0.1% (v/v) Triton X-100 partially solubilized the oestrogen-binding component(s) of plasma membranes. Particle-free extracts were resolved on 5–20% (w/v) sucrose density gradients with either 0.01m- or 0.4m-KCl, and the fractions were analysed by adsorption to hydroxyapatite. In low-salt gradients macromolecule-bound oestrogen sedimented at predominantly 7.4S and binding was 1560 times that of the homogenate. Under high-salt conditions oestradiol-binding activity occurred at both 3.6S and 4.9S.

scholarly journals Interaction of Azospirillum lipoferumwith Wheat Germ Agglutinin Stimulates Nitrogen Fixation

1999 ◽  
Vol 181 (13) ◽  
pp. 3949-3955 ◽  
Author(s):  
Eva Karpati ◽  
Peter Kiss ◽  
Tamas Ponyi ◽  
Istvan Fendrik ◽  
Miklos de Zamaroczy ◽  
...  
Keyword(s):  
Nitrogen Fixation ◽  
Gene Cluster ◽  
Binding Sites ◽  
Wheat Germ Agglutinin ◽  
Wheat Germ ◽  
Side Chains ◽  
Receptor Complex ◽  
Sugar Binding ◽  
Signalling Cascade

ABSTRACT In vitro, the nitrogen fixation capability of A. lipoferum is efficiently increased in the presence of wheat germ agglutinin (WGA). A putative WGA-binding receptor, a 32-kDa protein, was detected in the cell capsule. The stimulatory effect requiredN-acetyl-d-glucosamine dimer (GlcNAcdi) terminated sugar side chains of the receptor and was dependent on the number of GlcNAcdi links involved in receptor-WGA interface. Binding to the primary sugar binding sites on WGA had a larger stimulatory effect than binding to the secondary sites. The WGA-receptor complex generated stimulus led to elevated transcription of the nifH and nifA genes and of the glnBA gene cluster but not of the glnA gene from its own promoter. There may well be a signalling cascade contributing to the regulation of nitrogen fixation.

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