title: Molecular mechanism underlying the association of Coronin-7 with Golgi membranes.
abstract: Coronin-7 (Crn7) is a ubiquitous mammalian WD40-repeat protein that localizes to the Golgi complex, interacts with AP-1 adaptor complex via binding of a tyrosine-288-based sorting signal to the mu1-subunit of AP-1, and participates in the maintenance of the Golgi structure and function. Here, we define the requirements for the recruitment of Crn7 from the cytosol to the Golgi. We establish that Src activity is indispensable for the interaction of Crn7 with Golgi membranes. Crn7 binds Src in vivo and can be phosphorylated by recombinant Src in vitro. We demonstrate that tyrosine-758 is the major Src phosphorylation site. Further, to be targeted to membranes Crn7 requires the presence of cargo in the Golgi complex. Finally, downregulation of the mu1-subunit of AP-1 leads to the dispersal of Crn7 from the Golgi membranes. We propose a mechanism whereby sequential events of protein interaction and posttranslational modification result in the membrane targeting of Crn7.
authors.affiliation: Institute for Biochemistry I, University of Cologne, Joseph-Stelzmann-Str. 52, Cologne, Germany. vrybakin@scripps.edu
authors.forename: V
authors.initials: V
authors.lastname: Rybakin
authors.forename: R H
authors.initials: RH
authors.lastname: Rastetter
authors.forename: M
authors.initials: M
authors.lastname: Stumpf
authors.forename: A C
authors.initials: AC
authors.lastname: Uetrecht
authors.forename: J E
authors.initials: JE
authors.lastname: Bear
authors.forename: A A
authors.initials: AA
authors.lastname: Noegel
authors.forename: C S
authors.initials: CS
authors.lastname: Clemen
mesh_terms: D033961:Adaptor Protein Complex 1 / Q000378:metabolism; D033983:Adaptor Protein Complex mu Subunits / Q000378:metabolism; D020126:Brefeldin A / Q000494:pharmacology; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D006056:Golgi Apparatus / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007425:Intracellular Membranes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008840:Microfilament Proteins / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D016392:Proto-Oncogene Proteins pp60(c-src) / Q000378:metabolism; D034741:RNA, Small Interfering / Q000378:metabolism; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D033961:Adaptor Protein Complex 1; D033983:Adaptor Protein Complex mu Subunits; D007211:Indoles; D008840:Microfilament Proteins; D034741:RNA, Small Interfering; C416927:SU 6656; D013449:Sulfonamides; C072061:coronin proteins; D020126:Brefeldin A; D016392:Proto-Oncogene Proteins pp60(c-src)