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Sequential phosphorylation of GRASP65 during mitotic Golgi disassembly
Danming Tang1, Hebao Yuan, Ole Vielemeyer
1Department of Molecular, Cellular and Developmental Biology, University of Michigan , 830 North University Avenue, Ann Arbor, MI 48109-1048 , USA.
Biology Open
|December 22, 2012
Summary
Golgi protein GRASP65 undergoes sequential phosphorylation and dephosphorylation at specific sites during cell division. Phosphorylation of T220/224 is crucial for Golgi fragmentation, ensuring proper cell division.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Golgi disassembly and reassembly are essential for cell division, requiring GRASP65 phosphorylation and dephosphorylation.
- The coordinated phosphorylation of GRASP65 during mitosis was previously unknown.
Purpose of the Study:
- To investigate the sequential phosphorylation and dephosphorylation of GRASP65 at specific sites during the cell cycle.
- To determine the roles of different phosphorylation sites in Golgi dynamics during mitosis.
Main Methods:
- Generation of phospho-specific antibodies for GRASP65 residues T220/T224, S277, and S376.
- Biochemical analysis using cdc2 and plk1.
- Microscopic studies employing double and triple labeling techniques.
- Expression of phosphorylation-resistant GRASP65 mutants.
Main Results:
- cdc2 phosphorylates T220/T224, S277, and S376; plk1 enhances this phosphorylation.
- Sequential phosphorylation and dephosphorylation patterns were observed for different sites during the cell cycle.
- Phospho-T220/224 is critical for mitotic Golgi fragmentation, more so than S277/S376.
- Dephosphorylation order during cytokinesis: T220/224 after S376, but before S277.
Conclusions:
- GRASP65 phosphorylation and dephosphorylation at distinct sites are sequentially regulated during mitosis.
- This sequential modification orchestrates Golgi disassembly and reassembly for cell division.
- Phosphorylation of the T220/224 site plays a critical role in mitotic Golgi fragmentation.
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