title: Identification of proteasome components required for apical localization of Chaoptin using functional genomics.
abstract: Abstract: the distinct localization of membrane proteins with regard to cell polarity is crucial for the structure and function of various organs in multicellular organisms. However, the molecules and mechanisms that regulate protein localization to particular subcellular domains are still largely unknown. To identify the genes involved in regulation of protein localization, the authors performed a large-scale screen using a Drosophila RNA interference (RNAi) library, by which Drosophila genes could be knocked down in a tissue- and stage-specific manner. Drosophila photoreceptor cells have a morphologically distinct apicobasal polarity, along which Chaoptin (Chp), a glycosylphosphatidylinositol (GPI)-anchored membrane protein, and the Na (+) , K(+) -ATPase are localized to the apical and basolateral domains, respectively. By examining the subcellular localization of these proteins, the authors identified 106 genes whose knockdown resulted in mislocalization of Chp and Na(+) , K(+) -ATPase. Gene ontology analysis revealed that the knockdown of proteasome components resulted in mislocalization of Chp to the basolateral plasma membrane. These results suggest that the proteasome is involved, directly or indirectly, in selective localization of Chp to the apical plasma membrane of Drosophila photoreceptor cells.
authors.affiliation: Research Group of Glycobiology and Glycotechnology ,  Tokyo ,  Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Yano
authors.forename: Miki
authors.initials: M
authors.lastname: Yamamoto-Hino
authors.forename: Wakae
authors.initials: W
authors.lastname: Awano
authors.forename: Kiyoko F
authors.initials: KF
authors.lastname: Aoki-Kinoshita
authors.forename: Kayoko
authors.initials: K
authors.lastname: Tsuda-Sakurai
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Okano
authors.forename: Satoshi
authors.initials: S
authors.lastname: Goto
mesh_terms: D000818:Animals; D016764:Cell Polarity / Q000235:genetics*; D030541:Databases, Genetic; D004330:Drosophila / Q000235:genetics / Q000378:metabolism; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D023281:Genomics; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D013347:Subcellular Fractions / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; D008562:Membrane Glycoproteins; C055093:chp protein, Drosophila; D046988:Proteasome Endopeptidase Complex