title: AMY-1 (associate of Myc-1) localization to the trans-Golgi network through interacting with BIG2, a guanine-nucleotide exchange factor for ADP-ribosylation factors.
abstract: AMY-1 (associate of Myc-1) was originally identified as a c-Myc-binding protein that enhances the c-Myc transcription activity, and subsequently found to interact with A-kinase-anchoring proteins (AKAPs), including AKAP149, S-AKAP84 and AKAP95. We show here that, using anti-AMY-1 antibodies we raised, AMY-1 localizes to the trans-Golgi network (TGN) and the nucleus. To explore the possible function of AMY-1, we have undertaken a search for interacting partners by co-immunoprecipitation experiments using cells stably expressing FLAG-tagged AMY-1. Interestingly, we have found that AMY-1 interacts with BIG2 and BIG1, both of which are high molecular weight guanine-nucleotide exchange factors for ADP-ribosylation factors (ARFs) and mainly localize to the TGN. Furthermore, we have demonstrated that AMY-1 is associated with the TGN through interacting with BIG2 but not with BIG1 using an RNA interference approach, although AMY-1 can interact with both BIG1 and BIG2 in vitro. Taken together with the facts that BIG2 contains domains that bind to regulatory subunits of protein kinase A and that recruitment of ARF1 onto Golgi membranes is mediated, at least in part, by activation of protein kinase A, these results suggest that BIG2 alone or in concert with recruited AMY-1 coordinates ARF-mediated membrane trafficking and signaling pathways.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan.
authors.forename: Ray
authors.initials: R
authors.lastname: Ishizaki
authors.forename: Hye-Won
authors.initials: HW
authors.lastname: Shin
authors.forename: Sanae M M
authors.initials: SM
authors.lastname: Iguchi-Ariga
authors.forename: Hiroyoshi
authors.initials: H
authors.lastname: Ariga
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Nakayama
mesh_terms: D020727:ADP-Ribosylation Factors / Q000378:metabolism*; D000818:Animals; D016466:CHO Cells; D015816:Cell Adhesion Molecules, Neuronal / Q000378:metabolism*; D058966:Contactins; D006224:Cricetinae; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D047468:Immunoprecipitation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000378:metabolism; D014018:Tissue Distribution; D014157:Transcription Factors / Q000378:metabolism*; D021601:trans-Golgi Network / Q000378:metabolism*
chemical_list: C119087:ARFGEF1 protein, human; C098304:CNTN4 protein, human; D015816:Cell Adhesion Molecules, Neuronal; D058966:Contactins; D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; C116115:MYCBP protein, human; D021122:Protein Subunits; D014157:Transcription Factors; D017868:Cyclic AMP-Dependent Protein Kinases; D020727:ADP-Ribosylation Factors