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Isoform-specific tethering links the Golgi ribbon to maintain compartmentalization
- Source :
- Molecular Biology of the Cell
- Publication Year :
- 2014
- Publisher :
- American Society for Cell Biology (ASCB), 2014.
-
Abstract
- Use of photoinactivation, cisternae-specific fluorescence recovery, and high-resolution microscopy shows that the membrane tethers GRASP65 and GRASP55 on early and late Golgi membranes, respectively, are critical to the specific, homotypic fusion of the membranes on which they reside.<br />Homotypic membrane tethering by the Golgi reassembly and stacking proteins (GRASPs) is required for the lateral linkage of mammalian Golgi ministacks into a ribbon-like membrane network. Although GRASP65 and GRASP55 are specifically localized to cis and medial/trans cisternae, respectively, it is unknown whether each GRASP mediates cisternae-specific tethering and whether such specificity is necessary for Golgi compartmentalization. Here each GRASP was tagged with KillerRed (KR), expressed in HeLa cells, and inhibited by 1-min exposure to light. Significantly, inactivation of either GRASP unlinked the Golgi ribbon, and the immediate effect of GRASP65-KR inactivation was a loss of cis- rather than trans-Golgi integrity, whereas inactivation of GRASP55-KR first affected the trans- and not the cis-Golgi. Thus each GRASP appears to play a direct and cisternae-specific role in linking ministacks into a continuous membrane network. To test the consequence of loss of cisternae-specific tethering, we generated Golgi membranes with a single GRASP on all cisternae. Remarkably, the membranes exhibited the full connectivity of wild-type Golgi ribbons but were decompartmentalized and defective in glycan processing. Thus the GRASP isoforms specifically link analogous cisternae to ensure Golgi compartmentalization and proper processing.
- Subjects :
- Glycosylation
Vesicular Transport Proteins
Golgi Apparatus
Golgi reassembly
Biology
Endoplasmic Reticulum
Autoantigens
Time-Lapse Imaging
03 medical and health sciences
symbols.namesake
0302 clinical medicine
Polysaccharides
Humans
Protein Isoforms
Molecular Biology
030304 developmental biology
0303 health sciences
Tethering
Endoplasmic reticulum
Golgi Matrix Proteins
Membrane Proteins
Intracellular Membranes
Articles
Cell Biology
Golgi apparatus
Compartmentalization (psychology)
Transport protein
Cell biology
body regions
Protein Transport
Microscopy, Fluorescence
Membrane protein
Membrane Trafficking
symbols
Protein Processing, Post-Translational
030217 neurology & neurosurgery
HeLa Cells
Subjects
Details
- ISSN :
- 19394586 and 10591524
- Volume :
- 25
- Database :
- OpenAIRE
- Journal :
- Molecular Biology of the Cell
- Accession number :
- edsair.doi.dedup.....25a52c17526a65f5be1aa684733d51a1