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Quantitative Localization of a Golgi Protein by Imaging Its Center of Fluorescence Mass
Published on: August 10, 2017
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Isoform-specific tethering links the Golgi ribbon to maintain compartmentalization
Timothy Jarvela1, Adam D Linstedt
1Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213.
Molecular Biology of the Cell
|November 15, 2013
Summary
Golgi reassembly and stacking proteins (GRASPs) ensure proper Golgi structure. Specific GRASPs link similar Golgi compartments, maintaining organization and function.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Golgi reassembly and stacking proteins (GRASPs) mediate homotypic membrane tethering.
- GRASPs link mammalian Golgi ministacks into ribbon-like networks.
- GRASP65 and GRASP55 localize to cis and medial/trans cisternae, respectively.
Purpose of the Study:
- To investigate if GRASP65 and GRASP55 mediate cisternae-specific tethering.
- To determine if this specificity is essential for Golgi compartmentalization.
Main Methods:
- GRASPs were tagged with KillerRed (KR) and expressed in HeLa cells.
- GRASP activity was inhibited by light exposure.
- Golgi integrity and compartmentalization were assessed after GRASP inactivation.
Main Results:
- Inactivation of either GRASP disrupted the Golgi ribbon structure.
- GRASP65 inactivation primarily affected cis-Golgi integrity.
- GRASP55 inactivation primarily affected trans-Golgi integrity.
- Creating Golgi with a single GRASP on all cisternae resulted in connected but decompartmentalized membranes.
Conclusions:
- GRASP65 and GRASP55 play specific roles in linking analogous Golgi cisternae.
- This cisternae-specific tethering is crucial for maintaining Golgi compartmentalization.
- Proper compartmentalization ensures correct glycan processing within the Golgi apparatus.
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