title: The novel Rab11-FIP/Rip/RCP family of proteins displays extensive homo- and hetero-interacting abilities.
abstract: The Rab11-FIP/Rip/RCP proteins are a recently described novel protein family, whose members interact with Rab GTPases that function in endosomal recycling. To date, five such proteins have been described in humans, all of which interact with Rab11, and one (RCP) also interacts with Rab4. Here, we characterise several of these proteins with respect to their ability to interact with Rab4, as well as their ability to self-interact, and to interact with each other. We now demonstrate that two of the family members-pp75/Rip11 and Rab11-FIP3 do not bind Rab4 and show that several members of the family can self-interact and interact with each other. These interactions primarily involve their C-terminal end which includes the Rab binding domain (RBD) that is contained within a predicted coiled-coil, or ERM motif. We identify a new (sixth) member of the protein family, which we propose to name Rab11-FIP4, and report the family evolutionary complexity and chromosomal distribution. Furthermore, we propose that the ability of these proteins to bind each other will be important in effecting membrane trafficking events by forming protein 'platforms,' regulated by Rab11 and/or Rab4 activity.
authors.affiliation: Cell and Molecular Biology Laboratory, Department of Biochemistry, University College Cork, Lee Maltings, Prospect Row, Cork, Ireland.
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Wallace
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Lindsay
authors.forename: Alan G
authors.initials: AG
authors.lastname: Hendrick
authors.forename: Mary W
authors.initials: MW
authors.lastname: McCaffrey
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002874:Chromosome Mapping; D002877:Chromosomes, Human / Q000235:genetics; D019295:Computational Biology; D017124:Conserved Sequence; D019143:Evolution, Molecular; D006801:Humans; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000502:physiology; D021381:Protein Transport; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D009626:Terminology as Topic; D020798:Two-Hybrid System Techniques; D020691:rab GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020695:rab4 GTP-Binding Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D000099193:rab11 GTP-Binding Proteins
chemical_list: D002352:Carrier Proteins; D020691:rab GTP-Binding Proteins; D020695:rab4 GTP-Binding Proteins; D000099193:rab11 GTP-Binding Proteins; C439063:RAB11FIP3 protein, human