Cell wall constrains lateral diffusion of plant plasma-membrane proteins.
A cell membrane can be considered a liquid-phase plane in which lipids and proteins theoretically are free to diffuse. Numerous reports, however, describe retarded diffusion of membrane proteins in animal cells. This anomalous diffusion results from a combination of structuring factors including protein-protein interactions, cytoskeleton corralling, and lipid organization into microdomains. In plant cells, plasma-membrane (PM) proteins have been described as relatively immobile, but the control mechanisms that structure the PM have not been studied. Here, we use fluorescence recovery after photobleaching to estimate mobility of a set of minimal PM proteins. These proteins consist only of a PM-anchoring domain fused to a fluorescent protein, but their mobilities remained limited, as is the case for many full-length proteins. Neither the cytoskeleton nor membrane microdomain structure was involved in constraining the diffusion of these proteins. The cell wall, however, was shown to have a crucial role in immobilizing PM proteins. In addition, by single-molecule fluorescence imaging we confirmed that the pattern of cellulose deposition in the cell wall affects the trajectory and speed of PM protein diffusion. Regulation of PM protein dynamics by the plant cell wall can be interpreted as a mechanism for regulating protein interactions in processes such as trafficking and signal transduction.
Department of Biological and Medical Sciences,  Oxford Brookes University, Oxford OX3 0BP,  United Kingdom.
Alexandre
A
Martinière
Irene
I
Lavagi
Gayathri
G
Nageswaran
Daniel J
DJ
Rolfe
Lilly
L
Maneta-Peyret
Doan-Trung
DT
Luu
Stanley W
SW
Botchway
Stephen E D
SE
Webb
Sebastien
S
Mongrand
Christophe
C
Maurel
Marisa L
ML
Martin-Fernandez
Jürgen
J
Kleine-Vehn
Jirí
J
Friml
Patrick
P
Moreau
John
J
Runions
D017360:Arabidopsis / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000235:genetics / Q000378:metabolism*; D003599:Cytoskeleton / Q000235:genetics / Q000378:metabolism; D021962:Membrane Microdomains / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D021381:Protein Transport / Q000502:physiology; D014026:Nicotiana / Q000166:cytology / Q000235:genetics / Q000378:metabolism*
D029681:Arabidopsis Proteins; D008565:Membrane Proteins