Receptor diffusion on cell surfaces modulated by locally bound concanavalin A.
In order to test the anchorage modulation hypothesis, the fluorescence photobleaching recovery method was used to measure the global inhibition of cell surface receptor mobility induced in 3T3 mouse fibroblasts by local binding of platelets labeled with concanavalin A (Con A). By measuring the diffusion of antibody-labeled cell surface receptors at various points on the cell surface, two states, immobile and mobile, were distinguished in the receptor population. Bound Con A-platelets, occupying between 4% and 30% of the cell surface, decreased the diffusion coefficient of the mobile population by a factor of 6. The magnitude of this effect was independent of distance from the sites of the bound Con A-platelets, demonstrating the propagated and nonlocal properties of the modulation effect. The immobile fraction of the population was not changed by Con A-platelet binding. Modulation of the diffusion constant of mobile receptors was partially reversed by treatment with microtubule-disrupting agents such as Colcemid and Vinca alkaloids. High doses of soluble Con A induced even higher levels of modulation than Con A-platelets, but reversal by microtubule-disrupting drugs was observed. These experiments provide additional support for the anchorage modulation hypothesis and provide a measure of the nature and degree of mobility at the molecular level. They also put important constraints on the hypothesized interactions among submembranous components (microtubules and microfilaments) of surface modulating assemblies.
D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm; D001792:Blood Platelets; D002460:Cell Line; D002462:Cell Membrane / Q000276:immunology / Q000502:physiology* / Q000648:ultrastructure; D003703:Demecolcine / Q000494:pharmacology; D004058:Diffusion; D011034:Podophyllotoxin / Q000494:pharmacology; D011952:Receptors, Concanavalin A / Q000502:physiology*; D011955:Receptors, Drug / Q000502:physiology*; D012995:Solubility; D014747:Vinblastine / Q000494:pharmacology
D000936:Antigen-Antibody Complex; D000951:Antigens, Neoplasm; D011952:Receptors, Concanavalin A; D011955:Receptors, Drug; D014747:Vinblastine; D011034:Podophyllotoxin; D003703:Demecolcine
Science. 1977 Jan 21;195(4275):307-9
556653
Biophys J. 1976 Sep;16(9):1055-69
786399
Proc Natl Acad Sci U S A. 1976 Dec;73(12):4594-8
1070010
Nature. 1976 Nov 18;264(5583):226-31
1034208
Nature. 1976 Dec 9;264(5586):550-2
1004593
Biophys J. 1976 Nov;16(11):1315-29
974223
Proc Natl Acad Sci U S A. 1976 Jun;73(6):2047-51
180536
Proc Natl Acad Sci U S A. 1975 Mar;72(3):1127-31
48249
Exp Cell Res. 1973 Sep;81(1):143-55
4543272
Proc Natl Acad Sci U S A. 1974 Apr;71(4):1149-53
4545428
Proc Natl Acad Sci U S A. 1976 Jul;73(7):2409-13
1065895
Science. 1976 Apr 16;192(4236):218-26
769162
Proc Natl Acad Sci U S A. 1975 Apr;72(4):1579-83
1055429
Exp Cell Res. 1975 Mar 1;91(1):125-42
1132413