The localization and phosphorylation of p47 are important for Golgi disassembly-assembly during the cell cycle.
In mammalian cells, the Golgi apparatus is disassembled at the onset of mitosis and reassembled at the end of mitosis. This disassembly-reassembly is generally believed to be essential for the equal partitioning of Golgi into two daughter cells. For Golgi disassembly, membrane fusion, which is mediated by NSF and p97, needs to be blocked. For the NSF pathway, the tethering of p115-GM130 is disrupted by the mitotic phosphorylation of GM130, resulting in the inhibition of NSF-mediated fusion. In contrast, the p97/p47 pathway does not require p115-GM130 tethering, and its mitotic inhibitory mechanism has been unclear. Now, we have found that p47, which mainly localizes to the nucleus during interphase, is phosphorylated on Serine-140 by Cdc2 at mitosis. The phosphorylated p47 does not bind to Golgi membranes. An in vitro assay shows that this phosphorylation is required for Golgi disassembly. Microinjection of p47(S140A), which is unable to be phosphorylated, allows the cell to keep Golgi stacks during mitosis and has no effect on the equal partitioning of Golgi into two daughter cells, suggesting that Golgi fragmentation-dispersion may not be obligatory for equal partitioning even in mammalian cells.
Uchiyama
Keiji
K
Cambridge Institute for Medical Research, University of Cambridge, Cambridge CB2 2XY, UK. hk228@cam.ac.uk
Jokitalo
Eija
E
Lindman
Mervi
M
Jackman
Mark
M
Kano
Fumi
F
Murata
Masayuki
M
Zhang
Xiaodong
X
Kondo
Hisao
H
D000251:Adenosine Triphosphatases; D000818:Animals; D016203:CDC2 Protein Kinase / Q000378:metabolism; D002453:Cell Cycle / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism / Q000648:ultrastructure; D053487:DEAD-box RNA Helicases; D005057:Eukaryotic Cells / Q000378:metabolism* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D007399:Interphase / Q000502:physiology; D007425:Intracellular Membranes / Q000378:metabolism; D008561:Membrane Fusion / Q000502:physiology; D008854:Microscopy, Electron; D008938:Mitosis / Q000502:physiology*; D009687:Nuclear Proteins / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding / Q000502:physiology; D021381:Protein Transport / Q000502:physiology; D051381:Rats; D012694:Serine / Q000378:metabolism; D000074405:Valosin Containing Protein
D018797:Cell Cycle Proteins; D009687:Nuclear Proteins; D012694:Serine; D016203:CDC2 Protein Kinase; C075446:Ddx39b protein, rat; D000251:Adenosine Triphosphatases; D053487:DEAD-box RNA Helicases; D000074405:Valosin Containing Protein