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Updated: Jun 17, 2026
13:08
Quantitative Localization of a Golgi Protein by Imaging Its Center of Fluorescence Mass
Published on: August 10, 2017
GRASP55 and GRASP65 play complementary and essential roles in Golgi cisternal stacking
1Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA.
The Journal of Cell Biology
|January 20, 2010
Summary
Golgi stack formation relies on GRASP55 and GRASP65 proteins. These proteins work together to stack Golgi cisternae through a shared mechanism, crucial for maintaining Golgi structure.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Golgi stack formation is essential for protein processing and transport.
- GRASP65 and GRASP55 are peripheral Golgi proteins implicated in Golgi stack integrity.
- The precise mechanism of GRASP protein cooperation in stacking cisternae remains unclear.
Purpose of the Study:
- To elucidate the mechanism by which GRASP55 and GRASP65 cooperate to stack Golgi cisternae.
- To investigate the role of GRASP protein oligomerization and phosphorylation in Golgi stacking.
Main Methods:
- RNA interference (siRNA) for targeted depletion of GRASP55 and GRASP65.
- Analysis of Golgi stack morphology and cisternal number.
- Expression of wild-type and mutant GRASP55 proteins.
Main Results:
- Depletion of either GRASP55 or GRASP65 reduced cisternal number per Golgi stack.
- Simultaneous knockdown of both proteins led to complete Golgi stack disassembly.
- GRASP55 forms oligomers via its N-terminal domain to stack membranes, regulated by C-terminal phosphorylation.
- Nonphosphorylatable GRASP55 mutants enhanced stacking and inhibited mitotic disassembly.
Conclusions:
- GRASP55 and GRASP65 utilize a common mechanism to stack mammalian Golgi cisternae.
- GRASP protein function is critical for maintaining Golgi structure during interphase and mitosis.
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