Membrane curvature induced by Arf1-GTP is essential for vesicle formation.
The GTPase Arf1 is considered as a molecular switch that regulates binding and release of coat proteins that polymerize on membranes to form transport vesicles. Here, we show that Arf1-GTP induces positive membrane curvature and find that the small GTPase can dimerize dependent on GTP. Investigating a possible link between Arf dimerization and curvature formation, we isolated an Arf1 mutant that cannot dimerize. Although it was capable of exerting the classical role of Arf1 as a coat receptor, it could not mediate the formation of COPI vesicles from Golgi-membranes and was lethal when expressed in yeast. Strikingly, this mutant was not able to deform membranes, suggesting that GTP-induced dimerization of Arf1 is a critical step inducing membrane curvature during the formation of coated vesicles.
Beck
Rainer
R
Biochemistry Center, Heidelberg University, Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany.
Sun
Zhe
Z
Adolf
Frank
F
Rutz
Chistoph
C
Bassler
Jochen
J
Wild
Klemens
K
Sinning
Irmgard
I
Hurt
Ed
E
Brügger
Britta
B
Béthune
Julien
J
Wieland
Felix
F
D020823:ADP-Ribosylation Factor 1 / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D019281:Dimerization; D006056:Golgi Apparatus / Q000378:metabolism; D006160:Guanosine Triphosphate / Q000737:chemistry* / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D050356:Lipid Metabolism; D008081:Liposomes; D008954:Models, Biological; D008958:Models, Molecular; D011485:Protein Binding; D020836:Protein Structure, Quaternary; D051381:Rats
D008081:Liposomes; D006160:Guanosine Triphosphate; D020823:ADP-Ribosylation Factor 1