title: Mena-GRASP65 interaction couples actin polymerization to Golgi ribbon linking.
abstract: In mammalian cells, the Golgi reassembly stacking protein 65 (GRASP65) has been implicated in both Golgi stacking and ribbon linking by forming trans-oligomers through the N-terminal GRASP domain. Because the GRASP domain is globular and relatively small, but the gaps between stacks are large and heterogeneous, it remains puzzling how GRASP65 physically links Golgi stacks into a ribbon. To explore the possibility that other proteins may help GRASP65 in ribbon linking, we used biochemical methods and identified the actin elongation factor Mena as a novel GRASP65-binding protein. Mena is recruited onto the Golgi membranes through interaction with GRASP65. Depleting Mena or disrupting actin polymerization resulted in Golgi fragmentation. In cells, Mena and actin were required for Golgi ribbon formation after nocodazole washout; in vitro, Mena and microfilaments enhanced GRASP65 oligomerization and Golgi membrane fusion. Thus Mena interacts with GRASP65 to promote local actin polymerization, which facilitates Golgi ribbon linking.
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048.
authors.forename: Danming
authors.initials: D
authors.lastname: Tang
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048.
authors.forename: Shijiao
authors.initials: S
authors.lastname: Huang
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048.
authors.forename: Hebao
authors.initials: H
authors.lastname: Yuan
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048.
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109-1048 Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI 48109-1048 yzwang@umich.edu.
authors.forename: Yanzhuang
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000199:Actins / Q000378:metabolism; D001324:Autoantigens / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism*; D000077614:Golgi Matrix Proteins; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology; D008565:Membrane Proteins / Q000378:metabolism*; D008840:Microfilament Proteins / Q000378:metabolism*; D058105:Polymerization; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics
chemical_list: D000199:Actins; D001324:Autoantigens; C511939:Enah protein, human; C108705:GORASP1 protein, human; D000077614:Golgi Matrix Proteins; D008565:Membrane Proteins; D008840:Microfilament Proteins; D034741:RNA, Small Interfering