title: Phosphorylation of golgin-160 by mixed lineage kinase 3.
abstract: Golgin-160 is a member of the coiled-coil family of golgin proteins, which are proposed to regulate the structure of the Golgi complex. The C-terminal two-thirds of golgin-160 is predicted to form a coiled-coil domain and the N-terminal head domain contains several putative binding domains, regulatory motifs and phosphorylation sites. Recently, it has been demonstrated that caspase-dependent cleavage of the golgin-160 head domain occurs rapidly after induction of apoptosis. The role of golgin-160 phosphorylation and the functional implications for Golgi structure have not been defined. In this study, we investigated the kinase(s) responsible for phosphorylation of golgin-160. Signaling through the small G-protein Rac and mixed-lineage-kinase-3 (MLK3) resulted in increased phosphorylation of golgin-160. The intracellular distribution of MLK3 overlapped with that of golgin-160 and the two proteins could be co-immunoprecipitated. In vitro kinase assays demonstrated that MLK3 directly phosphorylates golgin-160 in the N-terminal head region between residues 96 and 259. Overexpression of MLK3 caused an enhanced caspase-dependent cleavage of golgin-160 at Asp139. Golgin-160 is the first non-kinase substrate of MLK3 identified, and phosphorylation by MLK3 might modulate cleavage of golgin-160 during apoptosis.
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland-School of Pharmacy, Baltimore, MD 21201, USA.
authors.forename: Hyukjin
authors.initials: H
authors.lastname: Cha
authors.forename: Barbara L
authors.initials: BL
authors.lastname: Smith
authors.forename: Kathleen
authors.initials: K
authors.lastname: Gallo
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Machamer
authors.forename: Paul
authors.initials: P
authors.lastname: Shapiro
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001324:Autoantigens / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016466:CHO Cells; D002227:Carbazoles / Q000494:pharmacology; D006224:Cricetinae; D003412:Cricetulus; D006056:Golgi Apparatus / Q000378:metabolism; D000077614:Golgi Matrix Proteins; D006367:HeLa Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D042541:Intracellular Space / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding; D011499:Protein Processing, Post-Translational; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D021381:Protein Transport; D051057:Proto-Oncogene Proteins c-akt; D015398:Signal Transduction; D013379:Substrate Specificity; D014162:Transfection; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11
chemical_list: D001224:Aspartic Acid; D001324:Autoantigens; D002227:Carbazoles; D000077614:Golgi Matrix Proteins; D007211:Indoles; D020930:MAP Kinase Kinase Kinases; D008565:Membrane Proteins; D010446:Peptide Fragments; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11; C469298:CEP-11004; C108388:GOLGA3 protein, human