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The structural GDP/GTP cycle of human Arf6
Author(s) -
Pasqualato Sebastiano,
Ménétrey Julie,
Franco Michel,
Cherfils Jacqueline
Publication year - 2001
Publication title -
embo reports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.584
H-Index - 184
eISSN - 1469-3178
pISSN - 1469-221X
DOI - 10.1093/embo-reports/kve043
Subject(s) - myristoylation , adp ribosylation factor , rab , gtpase , context (archaeology) , gtpgammas , gtp' , gtp binding protein regulators , effector , biology , microbiology and biotechnology , small gtpase , g protein , chemistry , biochemistry , membrane , signal transduction , paleontology , enzyme , endoplasmic reticulum , golgi apparatus
The small GTP‐binding protein Arf6 coordinates membrane traffic at the plasma membrane with aspects of cytoskeleton organization. This function does not overlap with that of other members of the ADP‐ribosylation factor (Arf) family, although their switch regions, which are their major sites of interaction with regulators and effectors, have virtually identical sequences. Here we report the crystal structure of full‐length, non‐myristoylated human Arf6 bound to GTPγS. Unlike their GDP‐bound forms, the active forms of Arf6 and Arf1 are very similar. Thus, the switch regions are discriminatory elements between Arf isoforms in their inactive but not in their active forms, a property that may generalize to other families of small G proteins. This suggests that GTP‐bound Arfs may establish specific interactions outside the switch regions and/or be recognized in their cellular context rather than as isolated proteins. The structure also allows further insight into the lack of spontaneous GTPase activity of Arf proteins.