Dynamic molecular confinement in the plasma membrane by microdomains and the cytoskeleton meshwork.
It is by now widely recognized that cell membranes show complex patterns of lateral organization. Two mechanisms involving either a lipid-dependent (microdomain model) or cytoskeleton-based (meshwork model) process are thought to be responsible for these plasma membrane organizations. In the present study, fluorescence correlation spectroscopy measurements on various spatial scales were performed in order to directly identify and characterize these two processes in live cells with a high temporal resolution, without any loss of spatial information. Putative raft markers were found to be dynamically compartmented within tens of milliseconds into small microdomains (Ø <120 nm) that are sensitive to the cholesterol and sphingomyelin levels, whereas actin-based cytoskeleton barriers are responsible for the confinement of the transferrin receptor protein. A free-like diffusion was observed when both the lipid-dependent and cytoskeleton-based organizations were disrupted, which suggests that these are two main compartmentalizing forces at work in the plasma membrane.
Lenne
Pierre-François
PF
Institut Fresnel, Université Paul Cézanne, Marseille, France [2] CNRS UMR 6133, Marseille, France.
Wawrezinieck
Laure
L
Conchonaud
Fabien
F
Wurtz
Olivier
O
Boned
Annie
A
Guo
Xiao-Jun
XJ
Rigneault
Hervé
H
He
Hai-Tao
HT
Marguet
Didier
D
D000199:Actins / Q000378:metabolism; D000818:Animals; D019556:COS Cells; D002462:Cell Membrane / Q000737:chemistry / Q000502:physiology*; D002522:Chlorocebus aethiops; D002784:Cholesterol / Q000378:metabolism; D003599:Cytoskeleton / Q000737:chemistry / Q000502:physiology*; D004058:Diffusion; D006801:Humans; D021962:Membrane Microdomains / Q000737:chemistry / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism; D016192:Resting Phase, Cell Cycle / Q000502:physiology; D013107:Sphingolipids / Q000378:metabolism
D000199:Actins; D008565:Membrane Proteins; D013107:Sphingolipids; D002784:Cholesterol