title: Identification of a PDZ domain containing Golgi protein, GOPC, as an interaction partner of frizzled.
abstract: The frizzled gene is evolutionally conserved in a wide variety of organisms including mammals, and in Drosophila, frizzled is implicated in the development of planar polarity. We describe here the isolation and characterization of a Golgi protein, GOPC, as a frizzled interacting protein. GOPC comprises one PDZ domain, two coiled-coil motifs and two evolutionally conserved regions. Immunofluorescence studies indicated that a significant fraction of GOPC protein was localized in the Golgi apparatus. Using a series of deletion mutants, we show that both coiled-coil motifs and a C-terminal conserved region were required for its Golgi localization. Interestingly, deletion mutants that lack a N-terminal conserved region or coiled-coil motifs formed aggresome-like perinuclear structure. Interaction of GOPC and frizzled was observed both in vivo and in vitro, and the PDZ domain of GOPC and the C-terminal Ser/Thr-X-Val motif of frizzled were required for their interaction. Immunofluorescence studies indicated that, although frizzled was a membrane protein, it was localized at the Golgi apparatus as well, and colocalization of GOPC and frizzled at the Golgi apparatus was observed. Furthermore, when GOPC was coexpressed with frizzled, translocation of GOPC to the plasma membrane was observed. Importantly, brefeldin A interrupted not only the localization of GOPC to the Golgi apparatus but also the translocation of frizzled to the plasma membrane, indicating that the Golgi structure was required for the proper subcellular localization of frizzled. Taken together, these results indicate that GOPC may play a role in the vesicle transport of frizzled from the Golgi apparatus to the plasma membrane.
authors.affiliation: Department of Cell Biology, The Cancer Institute, Japanese Foundation for Cancer Research, 1-37-1 Kami-Ikebukuro, Toshima-Ku, Tokyo 170-8455, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Yao
authors.forename: T
authors.initials: T
authors.lastname: Maeda
authors.forename: S
authors.initials: S
authors.lastname: Takada
authors.forename: T
authors.initials: T
authors.lastname: Noda
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D019556:COS Cells; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D005455:Fluorescent Antibody Technique; D051157:Frizzled Receptors; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism*; D000077614:Golgi Matrix Proteins; D047908:Intracellular Signaling Peptides and Proteins; D051379:Mice; D008969:Molecular Sequence Data; D017434:Protein Structure, Tertiary; D011956:Receptors, Cell Surface / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter / Q000378:metabolism*; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques; D029867:Xenopus Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C113865:FZD8 protein, Xenopus; D051157:Frizzled Receptors; C403211:Fzd5 protein, mouse; D000077614:Golgi Matrix Proteins; C435484:Gopc protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter; D029867:Xenopus Proteins; D020126:Brefeldin A