title: GM130 is a parallel tetramer with a flexible rod-like structure and N-terminally open (Y-shaped) and closed (I-shaped) conformations.
abstract: GM130 is a cytoplasmic peripheral membrane protein localized on the cis side of the Golgi apparatus. GM130 is proposed to function as a membrane skeleton, maintaining the structure of the Golgi apparatus, and as a vesicle tether that facilitates vesicle fusion to the Golgi membrane. More than 60% of the GM130 molecule is believed to exist as coiled-coil structures with a probability above 90%, based on its primary amino acid sequence. The predicted coiled-coil region was similar to that of yeast Uso1p and its mammalian homolog, p115, both of which form coiled-coil homodimers. Therefore, GM130 has long been thought to form a homodimer with a rod-like shape. However, our biochemical and electron microscopical analyses revealed that GM130 is a parallel homotetramer with a flexible rod-like structure with I- and Y-shaped conformations. The structure of the N-terminal region may interchange between an open conformation (branched or Y-shaped) and a closed conformation (non-branched or I-shaped), possibly with the help of interacting molecules. This conformational change may alter the oligomeric state of the GM130 molecules and the function of GM130 in the vesicle tethering and the maintenance of the Golgi structure.
authors: Faculty of Life Sciences, Kyoto Sangyo University, Japan.
authors: Ryuichi
authors: R
authors: Ishida
authors: Nagahama Institute of Bio-Science and Technology, Shiga, Japan.
authors: Akitsugu
authors: A
authors: Yamamoto
authors: Graduate School of Pharmaceutical Sciences, Kyoto University, Japan.
authors: Kazuhisa
authors: K
authors: Nakayama
authors: Division of Oral Biochemistry, Graduate School of Medical and Dental Sciences, Niigata University, Japan.
authors: Miwa
authors: M
authors: Sohda
authors: Cell Biology, Fukuoka University School of Medicine, Japan.
authors: Yoshio
authors: Y
authors: Misumi
authors: Department of Bioscience and Bioinformatics, Kyushu Institute of Technology, Fukuoka, Japan.
authors: Takuo
authors: T
authors: Yasunaga
authors: Faculty of Life Sciences, Kyoto Sangyo University, Japan.
authors: Nobuhiro
authors: N
authors: Nakamura
mesh_terms: D000818:Animals; D001324:Autoantigens / Q000737:chemistry* / Q000648:ultrastructure; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry* / Q000648:ultrastructure; D008958:Models, Molecular; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D051381:Rats
chemical_list: D001324:Autoantigens; C097741:Golgin subfamily A member 2; D008565:Membrane Proteins
keywords: GRASP65; Golgi matrix; coiled coil; golgins; p115