The coiled-coil membrane protein golgin-84 is a novel rab effector required for Golgi ribbon formation.
Fragmentation of the mammalian Golgi apparatus during mitosis requires the phosphorylation of a specific subset of Golgi-associated proteins. We have used a biochemical approach to characterize these proteins and report here the identification of golgin-84 as a novel mitotic target. Using cryoelectron microscopy we could localize golgin-84 to the cis-Golgi network and found that it is enriched on tubules emanating from the lateral edges of, and often connecting, Golgi stacks. Golgin-84 binds to active rab1 but not cis-Golgi matrix proteins. Overexpression or depletion of golgin-84 results in fragmentation of the Golgi ribbon. Strikingly, the Golgi ribbon is converted into mini-stacks constituting only approximately 25% of the volume of a normal Golgi apparatus upon golgin-84 depletion. These mini-stacks are able to carry out protein transport, though with reduced efficiency compared with a normal Golgi apparatus. Our results suggest that golgin-84 plays a key role in the assembly and maintenance of the Golgi ribbon in mammalian cells.
Diao
Aipo
A
School of Biological Sciences, University of Manchester, Manchester M13 9PT, UK.
Rahman
Dinah
D
Pappin
Darryl J C
DJ
Lucocq
John
J
Lowe
Martin
M
D000818:Animals; D001324:Autoantigens; D004721:Endoplasmic Reticulum / Q000378:metabolism / Q000648:ultrastructure; D005057:Eukaryotic Cells / Q000378:metabolism* / Q000648:ultrastructure; D005786:Gene Expression Regulation / Q000502:physiology; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D000077614:Golgi Matrix Proteins; D006367:HeLa Cells; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism* / Q000648:ultrastructure; D008565:Membrane Proteins / Q000378:metabolism* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008868:Microtubule Proteins / Q000378:metabolism* / Q000648:ultrastructure; D008938:Mitosis / Q000235:genetics; D010750:Phosphoproteins / Q000378:metabolism; D021381:Protein Transport / Q000235:genetics; D034741:RNA, Small Interfering; D051381:Rats; D011993:Recombinant Fusion Proteins; D013347:Subcellular Fractions; D033921:Vesicular Transport Proteins; D014764:Viral Proteins; D020761:rab1 GTP-Binding Proteins / Q000378:metabolism* / Q000648:ultrastructure
D001324:Autoantigens; C060042:GOLGA5 protein, human; D000077614:Golgi Matrix Proteins; D008565:Membrane Proteins; D008868:Microtubule Proteins; D010750:Phosphoproteins; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D033921:Vesicular Transport Proteins; D014764:Viral Proteins; D020761:rab1 GTP-Binding Proteins