Isolation of125I-concanavalin A-labeled plasma membrane from unfertilized mouse eggs

1987 ◽  
Vol 16 (4) ◽  
pp. 303-310 ◽  
Author(s):  
Jeffrey Boldt ◽  
Don P. Wolf
Keyword(s):  
Plasma Membrane ◽  
Concanavalin A ◽  
Mouse Eggs

Participation of concanavalin A binding sites in the interaction between Trypanosoma cruzi and macrophages

1983 ◽  
Vol 62 (1) ◽  
pp. 287-299
Author(s):  
M.N. Meirelles ◽  
A. Martinez-Palomo ◽  
T. Souto-Padron ◽  
W. De Souza
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Trypanosoma Cruzi ◽  
Uniform Distribution ◽  
Concanavalin A ◽  
Binding Sites ◽  
Peritoneal Macrophages ◽  
Untreated Mouse ◽  
Mouse Peritoneal Macrophages

Untreated mouse peritoneal macrophages as well as macrophages treated with concanavalin A (ConA) were incubated in the presence of untreated or ConA-treated epimastigotes and trypomastigotes of Trypanosoma cruzi. Treatment of epimastigotes or trypomastigotes with ConA increased or decreased their uptake by macrophages, respectively. Treatment of their macrophages with ConA reduced by 70% and increased by five times the ingestion of epimastigotes and trypomastigotes, respectively. These results are discussed in relation to previous studies on the mobility of ConA receptors in the membrane of the parasite. Using fluorescein- or ferritin-labelled ConA we observed that ConA binding sites located on the plasma membrane of macrophages are internalized during endocytosis of T. cruzi, and observed in association with the membrane of the endocytic vacuole. Vacuoles without parasites showed a uniform distribution of ConA binding sites, while these sites were distributed in patches in vacuoles containing parasites. These results, in association with others previously reported, suggest the involvement of glycoproteins and/or glycolipids localized on the cell surface of T. cruzi and macrophages during the T. cruzi-macrophage interaction.

The dynamics of plasma membrane PtdIns(4,5)P2 at fertilization of mouse eggs

2002 ◽  
Vol 115 (10) ◽  
pp. 2139-2149 ◽  
Author(s):  
Guillaume Halet ◽  
Richard Tunwell ◽  
Tamas Balla ◽  
Karl Swann ◽  
John Carroll
Keyword(s):  
Plasma Membrane ◽  
De Novo ◽  
Confocal Imaging ◽  
Cortical Granule ◽  
Cortical Granules ◽  
Vegetal Cortex ◽  
Living Mouse ◽  
Cortical Granule Exocytosis ◽  
Phosphatidylinositol 4 ◽  
Mouse Eggs

A series of intracellular Ca2+ oscillations are responsible for triggering egg activation and cortical granule exocytosis at fertilization in mammals. These Ca2+ oscillations are generated by an increase in inositol 1,4,5-trisphosphate [Ins(1,4,5)P3], which results from the hydrolysis of phosphatidylinositol 4,5-bisphosphate[PtdIns(4,5)P2]. Using confocal imaging to simultaneously monitor Ca2+ and plasma membrane PtdIns(4,5)P2in single living mouse eggs we have sought to establish the relationship between the kinetics of PtdIns(4,5)P2 metabolism and the Ca2+ oscillations at fertilization. We report that there is no detectable net loss of plasma membrane PtdIns(4,5)P2either during the latent period or during the subsequent Ca2+oscillations. When phosphatidylinositol 4-kinase is inhibited with micromolar wortmannin a limited decrease in plasma membrane PtdIns(4,5)P2 is detected in half the eggs studied. Although we were unable to detect a widespread loss of PtdIns(4,5)P2, we found that fertilization triggers a net increase in plasma membrane PtdIns(4,5)P2 that is localized to the vegetal cortex. The fertilization-induced increase in PtdIns(4,5)P2 follows the increase in Ca2+, is blocked by Ca2+ buffers and can be mimicked, albeit with slower kinetics, by photoreleasing Ins(1,4,5)P3. Inhibition of Ca2+-dependent exocytosis of cortical granules, without interfering with Ca2+ transients, inhibits the PtdIns(4,5)P2 increase. The increase appears to be due to de novo synthesis since it is inhibited by micromolar wortmannin. Finally,there is no increase in PtdIns(4,5)P2 in immature oocytes that are not competent to extrude cortical granules. These studies suggest that fertilization does not deplete plasma membrane PtdIns(4,5)P2 and that one of the pathways for increasing PtdIns(4,5)P2 at fertilization is invoked by exocytosis of cortical granules.

Differential partitioning of plasma membrane proteins into the triton X-100-insoluble cytoskeleton fraction during concanavalin A-induced receptor redistribution

1989 ◽  
Vol 92 (1) ◽  
pp. 85-91
Author(s):  
W.F. Patton ◽  
M.R. Dhanak ◽  
B.S. Jacobson
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Cell Surface ◽  
Concanavalin A ◽  
Temporal Order ◽  
Surface Glycoprotein ◽  
Plasma Membrane Proteins ◽  
Cell Surface Glycoprotein ◽  
Extensive Cell ◽  
Triton X

The plasma membrane proteins of Dictyostelium discoideum were characterized with respect to their partitioning into the Triton-insoluble cytoskeleton fraction of the cell during concanavalin A-induced capping. Two fractions of plasma membrane-associated concanavalin A were identified; one that immediately associated with the cytoskeleton fraction via cell surface glycoproteins, and one that partitioned with the cytoskeleton only after extensive cell surface glycoprotein cross-linking. Three major classes of polypeptides were found in the plasma membrane that differed with respect to their partitioning properties into the cytoskeleton fraction. The temporal order of association of the polypeptides with the cytoskeleton during concanavalin A-induced capping corresponded to the strength of their association with the cytoskeleton fraction as determined by pH and ionic strength elution from unligated cytoskeletons.

scholarly journals Methylprednisolone inhibits uptake of Ca2+ and Na+ ions into concanavalin A-stimulated thymocytes

1997 ◽  
Vol 326 (2) ◽  
pp. 329-332 ◽  
Author(s):  
Frank BUTTGEREIT ◽  
Stefan KRAUSS ◽  
Martin D. BRAND
Keyword(s):  
Plasma Membrane ◽  
Concanavalin A ◽  
Membrane Properties ◽  
Mitochondrial Electron Transport Chain ◽  
Oxidation Reactions ◽  
Transport Chain ◽  
Cord Injury ◽  
Na Ions ◽  
Atp Supply ◽  
Na Uptake

The glucocorticoid drug methylprednisolone inhibits respiration in concanavalin A-stimulated rat thymocytes at concentrations that are relevant to its acute clinical efficacy against autoimmune diseases and spinal cord injury. Methylprednisolone affects several processes, including ion cycling, substrate oxidation reactions and RNA/DNA synthesis. The inhibition of respiration used to drive ATP-consuming cycles of Ca2+ and Na+ ions across the plasma membrane has been proposed to be either primary or secondary to restriction of cellular ATP supply. By comparing the effects of methylprednisolone with those of myxothiazol, an inhibitor of the mitochondrial electron transport chain, we show that the effects of methylprednisolone on Ca2+ and Na+ cycling are primary. We propose that methylprednisolone acts by affecting membrane properties to inhibit Ca2+ and Na+ uptake across the plasma membrane and to increase H+ uptake across the mitochondrial membrane, and that other effects are secondary.

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