title: Structural Basis for the Interaction between Golgi Reassembly-stacking Protein GRASP55 and Golgin45.
abstract: Golgin45 is required for normal Golgi structure and the transportation of protein from the ER. It forms a specific complex with GRASP55in vivoLittle is known regarding the molecular details of this interaction and its structural role in stacking of the Golgi complex. Here, we present the crystal structure of the GRASP domains of GRASP55 in complex with the Golgin45 C-terminal peptide, determined at 1.33 Å resolution. Similar to the structure of GRASP65 bound to GM130 reported recently, this structure reveals more than one interacting site and involves both PDZ1 and PDZ2 domains of the GRASP simultaneously. The C-terminal peptides of Golgin45 and GM130 present a conserved PDZ domain binding motif sequence and recognize the canonical PDZ-peptide binding groove of the PDZ1 domains of GRASP55 and GRASP65. A main difference in this recognition process resides in a structural rearrangement of GRASP65-GM130 that does not occur for the GRASP55-Golgin45 complex. The binding site at the cleft between the PDZ1 and PDZ2 domains of GRASP65 is dominated by hydrophobic interactions with GM130 that are not observed in the GRASP55-Golgin45 complex. In addition, a unique zinc finger structure is revealed in the GRASP55-Golgin45 complex crystal structure. Mutagenesis experiments support these structural observations and demonstrate that two of these sites are required to form a stable complex. Finally, a novel Golgi stacking model is proposed according to these structural findings.
authors.affiliation: From the State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China and.
authors.forename: Jianfeng
authors.initials: J
authors.lastname: Zhao
authors.affiliation: From the State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China and.
authors.forename: Bowen
authors.initials: B
authors.lastname: Li
authors.affiliation: From the State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China and.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Huang
authors.affiliation: the Centre de Recherche en Cancérologie de Marseille (CRCM), INSERM, CNRS, Aix-Marseille Université, Institut Paoli-Calmettes, 13009 Marseille, France.
authors.forename: Xavier
authors.initials: X
authors.lastname: Morelli
authors.affiliation: From the State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002, China and shining@fjirsm.ac.cn.
authors.forename: Ning
authors.initials: N
authors.lastname: Shi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D018360:Crystallography, X-Ray; D006056:Golgi Apparatus / Q000378:metabolism*; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D051379:Mice; D011485:Protein Binding; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D033921:Vesicular Transport Proteins / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; C000620875:Golgin45 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; D033921:Vesicular Transport Proteins; C523888:tamalin protein, mouse
keywords: BLZF1; GRASP55; Golgi; Golgi stacking; Golgin45; PDZ domain; metal ion-protein interaction; protein trafficking (Golgi); protein-protein interaction; zinc finger