scholarly journals Diffusion rates of cell surface antigens of mouse-human heterokaryons. III. Regulation of lateral diffusion rates by calcium ions.

1982 ◽  
Vol 95 (2) ◽  
pp. 453-462 ◽  
Author(s):  
M Edidin ◽  
T Wei ◽  
L Gotlib
Keyword(s):  
Plasma Membrane ◽  
Calcium Ions ◽  
Calcium Ion ◽  
Calcium Release ◽  
Lateral Diffusion ◽  
Surface Antigens ◽  
Ionophore A23187 ◽  
Cell Surface Antigens ◽  
Mhc Antigens ◽  
Diffusion Rates

In mouse-human heterokaryons, the lateral diffusion of major histocompatibility (MHC) antigens in the plasma membrane is enhanced by treatment of parent cells with ouabain. Ouabain treatment is ineffective if the medium lacks calcium ion, or if Verapamil, a blocker of calcium channels, is present. The divalent ionophore A23187 also enhances lateral diffusion of MHC antigens, to the same extent as ouabain, A23187 is effective only if calcium is present in the medium. Thus it appears that increased levels of cell calcium release constraints to lateral diffusion of MHC antigens.

scholarly journals Diffusion rates of cell surface antigens of mouse-human heterokaryons. II. Effect of membrane potential on lateral diffusion.

1977 ◽  
Vol 75 (2) ◽  
pp. 483-489 ◽  
Author(s):  
M Edidin ◽  
T Y Wei
Keyword(s):  
Membrane Potential ◽  
Cell Surface ◽  
Single Cell ◽  
Surface Membrane ◽  
Lateral Diffusion ◽  
Surface Antigens ◽  
Lateral Mobility ◽  
Cell Surface Antigens ◽  
Common Effect ◽  
Diffusion Rates

The rate of appearance, in a population of mouse-human heterokaryons, of cells with intermixed mouse and human surface antigens may be used to estimate the rate of lateral diffusion of the antigens in a single cell. Most heterokaryons appear to restrict diffusion of their surface antigens. These restrictions are altered by exposing either heterokaryons or their parent cells to conditions that change cell surface membrane potential. Media containing unphysiological concentrations of potassium ion, drugs, affecting the Na+,K+ ATPase, or a channel-forming antibiotic, gramicidin, all affect lateral mobility of cell surface antigens in a manner consistent with a common effect on membrane potential.

scholarly journals Role of L3T4 in antigen-driven activation of a class I-specific T cell hybridoma.

1985 ◽  
Vol 162 (1) ◽  
pp. 369-374 ◽  
Author(s):  
J L Greenstein ◽  
B Malissen ◽  
S J Burakoff
Keyword(s):  
T Cell ◽  
Cell Function ◽  
Surface Antigens ◽  
Class I ◽  
Surface Markers ◽  
Cell Surface Antigens ◽  
Mhc Antigens ◽  
Major Histo Compatibility Complex ◽  
Compatibility Complex

The expression of L3T4/Lyt-2 on murine T cells has led to the association of these surface markers with recognition of either class II or class I major histo-compatibility complex (MHC) antigens. It has been suggested that these T cell surface antigens interact with nonpolymorphic determinants on MHC antigens. We have examined the role of L3T4 in the recognition of H-2Dd by the T cell hybridoma, 3DT52.5. Mouse L cells transfected with either the H-2Dd gene, or with both the alpha and beta genes of I-Ak and the H-2Dd gene have been used to assess the role of an L3T4/la interaction at varying doses of H-2Dd. A role of L3T4 in activation of 3DT52.5 becomes evident only at limiting doses of antigen. It appears that an L3T4/la interaction can influence T cell function during suboptimal stimulation, implying that the L3T4/la interaction serves to raise the functional affinity of interaction between the T cell and the antigen-bearing cell.

Serologic Analyses of Cell-Surface Antigens ofAcanthamoebaspp. with Plasma Membrane Antisera*†

1977 ◽  
Vol 24 (2) ◽  
pp. 316-324 ◽  
Author(s):  
A. R. STEVENS ◽  
T. KILPATRICK ◽  
E. WILLAERT ◽  
A. CAPRONI
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Surface Antigens ◽  
Cell Surface Antigens

scholarly journals Temporal expression of membrane antigens during mouse spermatogenesis

1977 ◽  
Vol 74 (1) ◽  
pp. 86-97 ◽  
Author(s):  
CF Millete ◽  
AR Bellve
Keyword(s):  
Plasma Membrane ◽  
Cell Surface ◽  
Germ Cells ◽  
Surface Antigens ◽  
Spermatogenic Cells ◽  
Temporal Expression ◽  
Isolated Populations ◽  
Cell Surface Antigens ◽  
Membrane Antigens ◽  
Type A Spermatogonia

The temporal expression of cell surface antigens during mammalian spermatogenesis has been investigated using isolated populations of mouse germ cells. Spermatogenic cells at advanced stages of differentiation, including pachytene primary spermatocytes, round spermatids, and residual bodies of Regaud and mature spermatozoa, contain common antigenic membrane components which are not detected before the pachytene stage of the first meiotic prophase. These surface constituents are not detected on isolated populations of primitive type A spermatogonia, type A spermatogonia, type B spermatogonia, preleptotene primary spermatocytes, or leptotene and zygotene primary spermatocytes. These results have been demonstrated by immunofluorescence microscopy, by complement-mediated cytotoxicity, and by quantitative measurements of immunoglobulin (Ig) receptors on the plasma membrane of all cell populations examined. The cell surface antigens detected on germ cells are not found on mouse thymocytes, erythrocytes, or peripheral blood lymphocytes as determined by immunofluorescence and by cytotoxicity assays. Furthermore, absorption of antisera with kidney and liver tissue does not reduce the reactivity of the antibody preparations with spermatogenic cells, indicating that these antigenic determinants are specific to germ cells. This represents the first direct evidence for the ordered temporal appearance of plasma membrane antigens specific to particular classes of mouse spermatogenic cells. It appears that at late meiotic prophase, coincident with the production of pachytene primary spermatocytes, a variety of new components are inserted into the surface membranes of developing germ cells. The further identification and biochemical characterization of these constituents should facilitate an understanding of mammalian spermatogenesis at the molecular level.

Exocytosis reconstituted from the sea urchin egg is unaffected by calcium pretreatment of granules and plasma membrane

1988 ◽  
Vol 8 (4) ◽  
pp. 335-343 ◽  
Author(s):  
Tim Whalley ◽  
Michael Whitaker
Keyword(s):  
Plasma Membrane ◽  
Sea Urchin ◽  
Calcium Ions ◽  
Calcium Ion ◽  
Secretory Granules ◽  
Cortical Granules ◽  
Allosteric Activation ◽  
Ion Concentrations ◽  
Sea Urchin Egg ◽  
Reconstituted System

Micromolar calcium ion concentrations stimulate exocytosis in a reconstituted system made by recombining in the plasma membrane and cortical secretory granules of the sea urchin egg. The isolated cortical granules are unaffected by calcium concentrations up to 1 mM, nor do granule aggregates undergo any mutual fusion at this concentration. Both isolated plasma membrane and cortical granules can be pretreated with 1 mM Ca before reconstitution without affecting the subsequent exocytosis of the reconstituted system in response to micromolar calcium concentrations. On reconstitution, aggregated cortical granules will fuse with one another in response to micromolar calcium provided that one of their number is in contact with the plasma membrane. If exocytosis involves the generation of lipid fusogens, then these results suggest that the calcium-stimulated production of a fusogen can occur only when contiguity exists between cortical granules and plasma membrane. They also suggest that a substance involved in exocytosis can diffuse and cause piggy-back fusion of secretory granules that are in contact with the plasma membrane. Our results are also consistent with a scheme in which calcium ions cause a reversible, allosteric activation of an exocytotic protein.

scholarly journals Diffusion rates of cell surface antigens of mouse-human heterokaryons. I. Analysis of the population.

1977 ◽  
Vol 75 (2) ◽  
pp. 475-482 ◽  
Author(s):  
M Edidin ◽  
T Y Wei
Keyword(s):  
Cell Surface ◽  
Cytochalasin B ◽  
Lipid Membrane ◽  
Sendai Virus ◽  
Surface Antigens ◽  
Cell Surface Antigens ◽  
Diffusion Constants ◽  
Diffusion Rates

The rate of appearance, in a newly formed heterokaryon population, of cells bearing completely intermixed mouse and human surface antigens may be used to estimate diffusion constants for antigens on individual cells. From this estimate, it appears that the surface antigens in most cells do not diffuse at the rate expected, but rather move more slowly, by a factor of ten or more, than expected from either measured or calculated diffusion constants for proteins freely mobile in the plane of a lipid membrane. Differences in diffusion rates between cells are not due to effects of Sendai virus, or of trypsin. Restrictions on diffusion are apparently not due to cytochalasin B- or Colcemid-sensitive elements.

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