Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Autoantigens*
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Endoplasmic Reticulum / metabolism
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Endoplasmic Reticulum / ultrastructure
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Eukaryotic Cells / metabolism*
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Eukaryotic Cells / ultrastructure
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Gene Expression Regulation / physiology
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Golgi Apparatus / metabolism*
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Golgi Apparatus / ultrastructure
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Golgi Matrix Proteins
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HeLa Cells
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Humans
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Intracellular Membranes / metabolism*
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Intracellular Membranes / ultrastructure
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Membrane Proteins / metabolism*
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Membrane Proteins / ultrastructure
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Microscopy, Electron
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Microtubule Proteins / metabolism*
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Microtubule Proteins / ultrastructure
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Mitosis / genetics
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Phosphoproteins / metabolism
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Protein Transport / genetics
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RNA, Small Interfering
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Rats
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Recombinant Fusion Proteins
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Subcellular Fractions
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Vesicular Transport Proteins
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Viral Proteins
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rab1 GTP-Binding Proteins / metabolism*
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rab1 GTP-Binding Proteins / ultrastructure
Substances
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Autoantigens
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GOLGA5 protein, human
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Golgi Matrix Proteins
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Membrane Proteins
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Microtubule Proteins
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Phosphoproteins
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RNA, Small Interfering
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Recombinant Fusion Proteins
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Vesicular Transport Proteins
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Viral Proteins
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rab1 GTP-Binding Proteins