The modulation of microprojections on the lymphocyte membrane and the redistribution of membrane‐bound ligands, a correlation

Loor, Francis; Hägg, Lena-Britt

doi:10.1002/eji.1830051211

Cited by 46 publications

(13 citation statements)

References 48 publications

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“…One would naively expect the presence of microvilli to have at least one of two effects: (i) it might take longer for the probe to redistribute completely on a villous cell than on a smooth cell, resulting in a smaller apparent diffusion coefficient because microvilli effectively increase the total membrane area illuminated by the laser beam; (ii) recovery might be less than 100% if the lipid probe did not diffuse back up into the microvilli during the time scale of the experiment. We estimate, from published scanning electron micrographs of lymphocytes, that as much as half of the membrane surface area can be accounted for by microvilli, in agreement with other published estimates (29). The lack of a substantial effect as our cells flattened out and lost microvilli could be explained in several ways: a faster diffusion rate in the microvilli; a compensating increase in membrane viscosity as the adherent cells flatten out; or a simple failure in our intuitive expectation of the effect of microvilli on diffusion.…”

Section: Discussionsupporting

confidence: 89%

Lateral diffusion of surface immunoglobulin, Thy-1 antigen, and a lipid probe in lymphocyte plasma membranes

Dragsten

Henkart

Blumenthal

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

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Fluorescence photobleaching recovery was used to measure the lateral diffusion coefficient and mobile fraction of surface immunoglobulin (sIg), Thy-1 antigen, and a lipid probe in the plasma membrane of mouse lymphocytes. The lipid probe (3,3'-dioctadecylindocarbocyanine) had a mean (+SD) diffusion coefficient of (1.7 ± 0.3) X 10-8 cm2/sec, with essentially all of the probe mobile in the membrane. We detected little or no effect on the diffusion of this probe due to the presence of microvilli. Its diffusion was slightly restricted in capped regions. No differences in lipid probe mobility were detected between T and B cells. Fifty to 90% of the detectable sIg and Thy-1 antigen was free to move in the plane of the membrane with diffusion coefficients of t3 X 10-10 cm2/sec; the remainder was immobile. Crosslinking of slg with anti-Ig antibodies (in the presence of azide to inhibit capping) completely immobilized slg at high concentrations but failed to do so at low concentrations. Thy-1 antigen could not be immobilized with an IgG rabbit anti-mouse brain reagent without an additional layer of crosslinking antibody. In parallel labelings (in the absence of azide), capping of slg and Thy-1 antigen was observed only under crosslinking conditions sufficient to immobilize the membrane antigen. Sodium azide, colchicine, and cytochalasin B had no measurable effect on lipid probe, sIg, orIt is well established that many membrane components can move laterally in the plasma membrane (1, 2). In a number of systems, this lateral mobility has proved to be physiologically important: (i) histamine release by mast cells results from aggregation of Fc receptors for IgE on the cell surface (3-6); (ii) receptors for insulin and epidermal growth factor quickly aggregate on the cell surface after hormone binding, and many insulin-like actions are mimicked by the aggregation of insulin receptors with bivalent anti-insulin receptor antibodies in the absence of the hormone (7-9); (iii) lymphocytes can be stimulated to differentiate and proliferate by bivalent anti-Ig and also by lectins (10-15), which presumably aggregate particular membrane glycoproteins.An additional example of lateral movement of membrane components is provided by the capping process. Surface immunoglobulin (sIg), the antigen receptor on B lymphocytes, forms patches which then move toward one pole of the cell to form a cap when treated with bivalent anti-Ig. This also occurs upon exposure of polyvalent antigens to B 5163The publication costs of this article were defrayed in part by page charge payment. This article must therefore be hereby marked "advertisement" in accordance with 18 U. S. C. §1734 solely to indicate this fact.

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Section: Discussionsupporting

confidence: 89%

Lateral diffusion of surface immunoglobulin, Thy-1 antigen, and a lipid probe in lymphocyte plasma membranes

Dragsten

Henkart

Blumenthal

et al. 1979

Proc. Natl. Acad. Sci. U.S.A.

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“…It is well known that the lymphocyte surface is covered with numerous microvilli (41,42 (37,38). This is expected, in view of the complexity of cell surface (40).…”

Section: Methodsmentioning

confidence: 90%

Unconstrained lateral diffusion of concanavalin A receptors on bulbous lymphocytes.

Wu¹,

Tank²,

Webb³

1982

Proc. Natl. Acad. Sci. U.S.A.

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The lateral diffusion coefficient, D, of concanavalin A receptors and receptor complexes on the surface of lymphocytes and RDM4 Iymphomas is enhanced by several orders of magnitude to D > 5 x IO-9cm2/sec by induction of swelling of the cells to bulbous form. Treatments with concanavalin A or 7-nitrobenz-2-oxa-1,3-diazole-phallacidin induce blebs and the bulbous form. The resulting separation ofthe plasma membrane from most of the F-actin cytoskeleton is accompanied by release of constraints on lateral diffusion of the cell surface receptors, which allows the diffusivity of these glycoproteins to increase nearly to the limit allowed by membrane viscosity.Fluorescence photobleaching methods (1-4) have been providing valuable quantitative information on the diffusibility ofvarious cell surface components within the plasma membranes of living cells in the culture. Recent experiments have established two ubiquitous features (4-9): first, a large fraction ofcell surface proteins are not at all diffusible; second, the diffusivities of the mobile fractions are several orders of magnitude smaller than expected for unrestricted diffusion in a viscous lipid bilayer matrix (10, 11). A "fluid mosaic" membrane model (12) alone does not account for the nondiffusible protein fraction nor for the measured quantitatively slow diffusion.As a result of these observations, several mechanisms intrinsic to cellular organization have been proposed (13-17) to account for the restricted lateral diffusion ofcell surface proteins. A prevailing view suggests that the lateral diffusion of surface proteins is restricted by their interactions with the cytoskeletal elements, primarily microfilaments. Several recent experiments demonstrated that the diffusion coefficients of band 3 proteins on erythrocyte ghosts are greatly enhanced by chemical treatments that disrupt the spectrin-actin cortex (18)(19)(20). However, in cultured cells, the applications of cytotoxic drugs that disrupt cytoskeletal structure have generated only small effects on protein diffusion (6,9,21,22).In this communication, we report experiments on the diffusion of concanavalin A (Con A) receptors on murine spleen lymphocytes (MSL) and lymphoma RDM4 cells that were subjected to a treatment that swells the cells to spherical form and detaches them from the bulk of the F-actin cytoskeleton. We observed that, after treatment with Con A or with a phallotoxin, a small fraction of MSL and RDM4 cells swell to form spherical bulbous cells about twice their original diameter. Fluorescence staining of F-actin with 7-nitrobenz-2-oxa-1,3-diazole-phallacidin (NBD-phallacidin) (23) demonstrated that the bulk of the F-actin cortical cytoskeleton in these bulbous cells had separated from the cell periphery and remained as mesh tightly wrapped around the nucleus. We measured the lateral diffusion of Con A receptors in the plasma membranes of these bulbous cells by fluorescence photobleaching recovery (FPR) methods (2) and found that most Con A receptors were diffusible with an enhanc...

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“…Hammer and Apte (1992), for example, developed a model to describe a range of leukocyte-endothelial cell adhesive events such as rolling, tumbling, transient adhesion, and firm attachment, using dimensional parameters including the length and spring constants of microvilli. The values for microvillous length (Bongrand and Bell, 1984) and the number of microvilli per cell (Knutton et al, 1975;Loor and Hagg, 1975), however, were based on determinations from other cell types, and the average length of PMN microvilli was assumed to be 500 nm. This is almost twice the measured value of 290 nm determined here for PMN microvilli.…”

Section: Discussionmentioning

confidence: 99%

Quantitation of L-selectin distribution on human leukocyte microvilli by immunogold labeling and electron microscopy.

Bruehl

Springer²,

Bainton³

1996

J Histochem Cytochem.

139

133

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L-Selectin is a leukocyte cell adhesion receptor that contributes to neutrophil (PMN) rolling on activated endothelium at sites of idammation and mediates lymphocyte attachment to high endothelial venules in peripheral lymph nodes. Localization of this receptor to the tips of PMN and lymphocyte microvilli has been demonstrated. However, its distribution on these cells has not been quantified, and its localization on other leukocytes and the morphometry of microvilli on different leukocyte subpopulations have not been previously examined. In this study, PMN and mononuclear leukocytes were isolated from anticoagulated blood by dextran sedimentation and density centrifugation, fixed in 2% paraformaldehyde and 0.05% glutaraldehyde, immunogold-labeled for L-selectin, and embedded in Epon resin. The distribution of L-selectin was determined by counting gold particles on the plasma membrane of sectioned cells, and the surface microstructure of these cells was surveyed on two-dimensional transmission electron micrographs. On average, 78% of PMN, 72% of monocyte, and 71% of lymphocyte L-selectin was observed on the microvilli, with more Variance on lymphocytes than the other cell types. Typical PMN and monocyte sections had 26 microvilli, whereas typical lymphocyte sections had 23. Quantitation of the distribution of L-selectin and leukocyte surface topology offers a foundation from which to study the requirement of microvilli or microvillus-localized L-selectin for leukocyte tethering and rolling in model systems that mimic microvas-

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The modulation of microprojections on the lymphocyte membrane and the redistribution of membrane‐bound ligands, a correlation

Cited by 46 publications

References 48 publications

Lateral diffusion of surface immunoglobulin, Thy-1 antigen, and a lipid probe in lymphocyte plasma membranes

Lateral diffusion of surface immunoglobulin, Thy-1 antigen, and a lipid probe in lymphocyte plasma membranes

Unconstrained lateral diffusion of concanavalin A receptors on bulbous lymphocytes.

Quantitation of L-selectin distribution on human leukocyte microvilli by immunogold labeling and electron microscopy.

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