title: Systematic discovery of Rab GTPases with synaptic functions in Drosophila.
abstract: BACKGROUND
  Neurons require highly specialized intracellular membrane trafficking, especially at synapses. Rab GTPases are considered master regulators of membrane trafficking in all cells, and only very few Rabs have known neuron-specific functions. Here, we present the first systematic characterization of neuronal expression, subcellular localization, and function of Rab GTPases in an organism with a brain.
  
  
  RESULTS
  We report the surprising discovery that half of all Drosophila Rabs function specifically or predominantly in distinct subsets of neurons in the brain. Furthermore, functional profiling of the GTP/GDP-bound states reveals that these neuronal Rabs are almost exclusively active at synapses and the majority of these synaptic Rabs specifically mark synaptic recycling endosomal compartments. Our profiling strategy is based on Gal4 knockins in large genomic fragments that are additionally designed to generate mutants by ends-out homologous recombination. We generated 36 large genomic targeting vectors and transgenic rab-Gal4 fly strains for 25 rab genes. Proof-of-principle knockout of the synaptic rab27 reveals a sleep phenotype that matches its cell-specific expression.
  
  
  CONCLUSIONS
  Our findings suggest that up to half of all Drosophila Rabs exert specialized synaptic functions. The tools presented here allow systematic functional studies of these Rabs and provide a method that is applicable to any large gene family in Drosophila.
authors: Department of Physiology, UT Southwestern Medical Center, Dallas, TX 75390, USA.
authors: Chih-Chiang
authors: CC
authors: Chan
authors: Shane
authors: S
authors: Scoggin
authors: Dong
authors: D
authors: Wang
authors: Smita
authors: S
authors: Cherry
authors: Todd
authors: T
authors: Dembo
authors: Ben
authors: B
authors: Greenberg
authors: Eugene Jennifer
authors: EJ
authors: Jin
authors: Cansu
authors: C
authors: Kuey
authors: Antonio
authors: A
authors: Lopez
authors: Sunil Q
authors: SQ
authors: Mehta
authors: Theodore J
authors: TJ
authors: Perkins
authors: Marko
authors: M
authors: Brankatschk
authors: Adrian
authors: A
authors: Rothenfluh
authors: Michael
authors: M
authors: Buszczak
authors: P Robin
authors: PR
authors: Hiesinger
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001921:Brain / Q000502:physiology; D022202:Chromosomes, Artificial, Bacterial; D004330:Drosophila / Q000235:genetics / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D055786:Gene Knockout Techniques; D059765:Homologous Recombination; D005810:Multigene Family; D009154:Mutation; D009474:Neurons / Q000378:metabolism; D009928:Organ Specificity; D010641:Phenotype; D013569:Synapses / Q000378:metabolism*; D020691:rab GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D000075745:rab27 GTP-Binding Proteins
chemical_list: D029721:Drosophila Proteins; D000075745:rab27 GTP-Binding Proteins; C574216:Rab27 protein, Drosophila; D020691:rab GTP-Binding Proteins