Structure and analysis of FCHo2 F-BAR domain: a dimerizing and membrane recruitment module that effects membrane curvature.
A spectrum of membrane curvatures exists within cells, and proteins have evolved different modules to detect, create, and maintain these curvatures. Here we present the crystal structure of one such module found within human FCHo2. This F-BAR (extended FCH) module consists of two F-BAR domains, forming an intrinsically curved all-helical antiparallel dimer with a Kd of 2.5 microM. The module binds liposomes via a concave face, deforming them into tubules with variable diameters of up to 130 nm. Pulse EPR studies showed the membrane-bound dimer is the same as the crystal dimer, although the N-terminal helix changed conformation on membrane binding. Mutation of a phenylalanine on this helix partially attenuated narrow tubule formation, and resulted in a gain of curvature sensitivity. This structure shows a distant relationship to curvature-sensing BAR modules, and suggests how similar coiled-coil architectures in the BAR superfamily have evolved to expand the repertoire of membrane-sculpting possibilities.
Henne
William Mike
WM
MRC Laboratory of Molecular Biology, Hills Road, Cambridge, CB1 0QH, United Kingdom.
Kent
Helen M
HM
Ford
Marijn G J
MG
Hegde
Balachandra G
BG
Daumke
Oliver
O
Butler
P Jonathan G
PJ
Mittal
Rohit
R
Langen
Ralf
R
Evans
Philip R
PR
McMahon
Harvey T
HT
D000595:Amino Acid Sequence; D002462:Cell Membrane / Q000737:chemistry*; D019281:Dimerization; D004578:Electron Spin Resonance Spectroscopy; D050556:Fatty Acid-Binding Proteins; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008081:Liposomes / Q000737:chemistry; D008565:Membrane Proteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry*
C497031:FCHO2 protein, human; D050556:Fatty Acid-Binding Proteins; D008081:Liposomes; D008565:Membrane Proteins; D011506:Proteins