title: Coat-tether interaction in Golgi organization.
abstract: Biogenesis of the Golgi apparatus is likely mediated by the COPI vesicle coat complex, but the mechanism is poorly understood. Modeling of the COPI subunit betaCOP based on the clathrin adaptor AP2 suggested that the betaCOP C terminus forms an appendage domain with a conserved FW binding pocket motif. On gene replacement after knockdown, versions of betaCOP with a mutated FW motif or flanking basic residues yielded a defect in Golgi organization reminiscent of that occurring in the absence of the vesicle tether p115. Indeed, betaCOP bound p115, and this depended on the betaCOP FW motif. Furthermore, the interaction depended on E(19)E(21) in the p115 head domain and inverse charge substitution blocked Golgi biogenesis in intact cells. Finally, Golgi assembly in permeabilized cells was significantly reduced by inhibitors containing intact, but not mutated, betaCOP FW or p115 EE motifs. Thus, Golgi organization depends on mutually interacting domains in betaCOP and p115, suggesting that vesicle tethering at the Golgi involves p115 binding to the COPI coat.
authors.affiliation: Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
authors.forename: Yusong
authors.initials: Y
authors.lastname: Guo
authors.forename: Vasu
authors.initials: V
authors.lastname: Punj
authors.forename: Debrup
authors.initials: D
authors.lastname: Sengupta
authors.forename: Adam D
authors.initials: AD
authors.lastname: Linstedt
mesh_terms: D020816:Amino Acid Motifs; D000818:Animals; D020756:Coatomer Protein / Q000737:chemistry* / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism*; D000077614:Golgi Matrix Proteins; D006367:HeLa Cells; D006801:Humans; D007668:Kidney / Q000378:metabolism; D008954:Models, Biological; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering / Q000378:metabolism; D051381:Rats; D020798:Two-Hybrid System Techniques; D033921:Vesicular Transport Proteins / Q000378:metabolism*
chemical_list: D020756:Coatomer Protein; D000077614:Golgi Matrix Proteins; D034741:RNA, Small Interfering; D033921:Vesicular Transport Proteins; C091580:vesicular transport factor p115