title: Differential membrane association properties and regulation of class I and class II Arfs.
abstract: ADP-ribosylation factor (Arf) proteins are small guanosine triphosphatases (GTPases) that act as major regulators of intracellular vesicular trafficking and secretory organelle pathway integrity. Like all small monomeric GTPases, Arf proteins cycle between a GDP-bound and a GTP-bound state, and this cycling is catalysed by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins. While the class I Arfs, especially Arf1, have been studied extensively, little is known as yet about the function and regulation of class II Arfs, Arf4 and Arf5. In this study, we show that Arf proteins show class-specific dynamic behaviour. Moreover, unlike class I Arfs, membrane association of class II Arfs is resistant to inhibition of large Arf GEFs by Brefeldin A. Through the construction of Arf chimeric proteins, evidence is provided that the N-terminal amphipathic helix and a class-specific residue in the conserved interswitch domain determine the membrane-binding properties of class I and class II Arf proteins. Our results show that fundamental differences exist in behaviour and regulation of these small GTPases.
authors.affiliation: Department of Medical Microbiology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: Daniël
authors.initials: D
authors.lastname: Duijsings
authors.forename: Kjerstin H W
authors.initials: KH
authors.lastname: Lanke
authors.forename: Sander H J
authors.initials: SH
authors.lastname: van Dooren
authors.forename: Michiel M T
authors.initials: MM
authors.lastname: van Dommelen
authors.forename: Roy
authors.initials: R
authors.lastname: Wetzels
authors.forename: Fabrizio
authors.initials: F
authors.lastname: de Mattia
authors.forename: Els
authors.initials: E
authors.lastname: Wessels
authors.forename: Frank J M
authors.initials: FJ
authors.lastname: van Kuppeveld
mesh_terms: D020727:ADP-Ribosylation Factors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D000882:Haplorhini; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011485:Protein Binding; D020033:Protein Isoforms / Q000378:metabolism; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D020662:Guanine Nucleotide Exchange Factors; D020033:Protein Isoforms; D020126:Brefeldin A; D020727:ADP-Ribosylation Factors