Multiple and stepwise interactions between coatomer and ADP-ribosylation factor-1 (Arf1)-GTP.
The small GTPase ADP-ribosylation factor-1 (Arf1) plays a key role in the formation of coat protein I (COP I)-coated vesicles. Upon recruitment to the donor Golgi membrane by interaction with dimeric p24 proteins, Arf1's GDP is exchanged for GTP. Arf1-GTP then dissociates from p24, and together with other Golgi membrane proteins, it recruits coatomer, the heptameric coat protein complex of COP I vesicles, from the cytosol. In this process, Arf1 was shown to specifically interact with the coatomer beta and gamma-COP subunits through its switch I region, and with epsilon-COP. Here, we mapped the interaction of the Arf1-GTP switch I region to the trunk domains of beta and gamma-COP. Site-directed photolabeling at position 167 in the C-terminal helix of Arf1 revealed a novel interaction with coatomer via a putative longin domain of delta-COP. Thus, coatomer is linked to the Golgi through multiple interfaces with membrane-bound Arf1-GTP. These interactions are located within the core, adaptor-like domain of coatomer, indicating an organizational similarity between the COP I coat and clathrin adaptor complexes.
Sun
Zhe
Z
Biochemie-Zentrum der Universität Heidelberg (BZH), Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany.
Anderl
Frank
F
Fröhlich
Kathrin
K
Zhao
Liyun
L
Hanke
Stefan
S
Brügger
Britta
B
Wieland
Felix
F
Béthune
Julien
J
D020823:ADP-Ribosylation Factor 1 / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D001577:Benzophenones / Q000737:chemistry; D001665:Binding Sites; D001692:Biological Transport / Q000502:physiology; D002417:Cattle; D020755:Coat Protein Complex I / Q000235:genetics / Q000378:metabolism*; D020756:Coatomer Protein / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D006056:Golgi Apparatus / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000031:analogs & derivatives / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism*; D008954:Models, Biological; D008969:Molecular Sequence Data; D019920:Photoaffinity Labels / Q000737:chemistry; D025941:Protein Interaction Mapping / Q000379:methods; D011817:Rabbits; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism
D001577:Benzophenones; D020755:Coat Protein Complex I; D020756:Coatomer Protein; D019920:Photoaffinity Labels; D011994:Recombinant Proteins; C047723:benzophenone; D006160:Guanosine Triphosphate; D020823:ADP-Ribosylation Factor 1