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Updated: Aug 8, 2026

Mapping Molecular Diffusion in the Plasma Membrane by Multiple-Target Tracing (MTT)
Published on: May 27, 2012
Lateral diffusion of human histocompatibility antigens in isolated plasma membranes
Abstract:
We have prepared large (5-10 microns) plasma membrane fragments by lysis of VA-2, human, cells adherent to Sephadex beads. The membrane fragments may be removed from beads by sonication and stained with fluorescent antibodies to human histocompatibility antigens, HLA antigens. Lateral diffusion of labelled antigens is followed by the method of fluorescence photobleaching recovery (FPR). HLA antigens of isolated membranes diffuse at the same rate, approx. (2-4) X 10(-10) cm2 X s-1 as they do in intact cells. This rate may be modified by incubating membranes in a variety of media. Buffers of slightly acid pH (6.5 or less) enhance lateral diffusion, while the presence of divalent ions slightly reduces diffusion rates. Our major finding is that incubation of 37 degrees in 0.10 M phosphate buffer increases lateral diffusion 3-5-fold.
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