CD4 interacts constitutively with multiple CCR5 at the plasma membrane of living cells. A fluorescence recovery after photobleaching at variable radii approach.
The entry of human immunodeficiency virus into target cells requires successive interactions of the viral envelope glycoprotein gp120 with CD4 and the chemokine receptors CCR5 or CXCR4. We previously demonstrated, by Förster resonance energy transfer experiments, the constitutive association of CD4 and CCR5 at the surface of living cells. We therefore speculated that this interaction may correlate with compartmentalization of CD4 and CCR5 within the plasma membrane. Here, we characterize the lateral distribution, the dynamics, and the stoichiometry of these receptors in living cells stably expressing CD4 and/or CCR5 by means of fluorescence recovery after photobleaching at variable radii experiments. We found that (i) these receptors expressed alone are confined into 1-microm-sized domains, (ii) CD4-CCR5 associations occur outside and inside smaller domains, and (iii) these interactions involve multiple CCR5 molecules per CD4.
Baker
Aurélie-Marie
AM
Institut de Pharmacologie et Biologie Structurale, UMR CNRS-Université Paul Sabatier 5089, 205 Route de Narbonne, 31062 Toulouse cedex, France.
Saulière
Aude
A
Gaibelet
Gérald
G
Lagane
Bernard
B
Mazères
Serge
S
Fourage
Marie
M
Bachelerie
Françoise
F
Salomé
Laurence
L
Lopez
André
A
Dumas
Fabrice
F
D001703:Biophysics / Q000379:methods; D015704:CD4 Antigens / Q000096:biosynthesis*; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D018076:DNA, Complementary / Q000378:metabolism; D004058:Diffusion; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods; D005786:Gene Expression Regulation; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006801:Humans; D018613:Microscopy, Confocal; D008954:Models, Biological; D011485:Protein Binding; D019713:Receptors, CCR5 / Q000378:metabolism*
D015704:CD4 Antigens; D018076:DNA, Complementary; D019713:Receptors, CCR5; D049452:Green Fluorescent Proteins