Anatomy and dynamics of a supramolecular membrane protein cluster.
Most plasmalemmal proteins organize in submicrometer-sized clusters whose architecture and dynamics are still enigmatic. With syntaxin 1 as an example, we applied a combination of far-field optical nanoscopy, biochemistry, fluorescence recovery after photobleaching (FRAP) analysis, and simulations to show that clustering can be explained by self-organization based on simple physical principles. On average, the syntaxin clusters exhibit a diameter of 50 to 60 nanometers and contain 75 densely crowded syntaxins that dynamically exchange with freely diffusing molecules. Self-association depends on weak homophilic protein-protein interactions. Simulations suggest that clustering immobilizes and conformationally constrains the molecules. Moreover, a balance between self-association and crowding-induced steric repulsions is sufficient to explain both the size and dynamics of syntaxin clusters and likely of many oligomerizing membrane proteins that form supramolecular structures.
Sieber
Jochen J
JJ
Department of Neurobiology, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany.
Willig
Katrin I
KI
Kutzner
Carsten
C
Gerding-Reimers
Claas
C
Harke
Benjamin
B
Donnert
Gerald
G
Rammner
Burkhard
B
Eggeling
Christian
C
Hell
Stefan W
SW
Grubmüller
Helmut
H
Lang
Thorsten
T
D020816:Amino Acid Motifs; D000818:Animals; D002462:Cell Membrane / Q000737:chemistry / Q000378:metabolism*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003198:Computer Simulation; D004058:Diffusion; D036681:Fluorescence Recovery After Photobleaching; D049452:Green Fluorescent Proteins; D015151:Immunoblotting; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D036103:Nanotechnology; D016716:PC12 Cells; D017434:Protein Structure, Tertiary; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000378:metabolism; D050827:Syntaxin 1 / Q000737:chemistry* / Q000378:metabolism*
D011993:Recombinant Fusion Proteins; D050827:Syntaxin 1; D049452:Green Fluorescent Proteins