Is the 6 kDa tobacco etch viral protein a bona fide ERES marker?
Open Access
- 24 June 2011
- journal article
- research article
- Published by Oxford University Press (OUP) in Journal of Experimental Botany
- Vol. 62 (14), 5013-5023
- https://doi.org/10.1093/jxb/err200
Abstract
The claim that the 6 kDa viral protein (VP) of Tobacco Etch Virus is a marker for ER exit sites (ERES) has been investigated. When transiently expressed as a CFP tagged fusion construct in tobacco mesophyll protoplasts, this integral membrane protein co-localizes with both the COPII coat protein YFP-SEC24 and the Golgi marker Man1-RFP. However, when over-expressed the VP locates to larger spherical structures which co-localize with neither ER nor Golgi markers. Nevertheless, deletion of the COPII interactive N-terminal D(X)E motif causes it to be broadly distributed throughout the ER, supporting the notion that this protein could be an ERES marker. Curiously, whereas brefeldin A (BFA) caused a typical Golgi-stack response (redistribution into the ER) of the VP in leaf epidermal cells, in protoplasts it resulted in the formation of structures identical to those formed by over-expression. However, anomalous results were obtained with protoplasts: when co-expressed with the non-cycling cis-Golgi marker Man1-RFP, a BFA-induced redistribution of the VP-CFP signal into the ER was observed, but, in the presence of the cycling Golgi marker ERD2-YFP, this did not occur. High resolution images of side-on views of Golgi stacks in epidermal cells showed that the 6 kDa VP-CFP signal overlapped considerably more with YFP-SEC24 than with Man1-RFP, indicating that the VP is proportionately more associated with ERES. However, based on a consideration of the structure of its cytoplasmic tail, the scenario that the VP collects at ERES and is transported to the cis-Golgi before being recycled back to the ER, is supported.Keywords
This publication has 53 references indexed in Scilit:
- Regulation of coat assembly—sorting things out at the ERCurrent Opinion in Cell Biology, 2010
- Sequential Depletion and Acquisition of Proteins during Golgi Stack Disassembly and ReformationTraffic, 2010
- TANGO1 Facilitates Cargo Loading at Endoplasmic Reticulum Exit SitesCell, 2009
- Nanoscale Architecture of Endoplasmic Reticulum Export Sites and of Golgi Membranes as Determined by Electron TomographyPlant Physiology, 2008
- Protein quality control in the early secretory pathwayThe EMBO Journal, 2008
- Golgi Regeneration after Brefeldin A Treatment in BY-2 Cells Entails Stack Enlargement and Cisternal Growth followed by DivisionPlant Physiology, 2007
- De Novo Formation of Plant Endoplasmic Reticulum Export Sites Is Membrane Cargo Induced and Signal MediatedPlant Physiology, 2007
- Sec16 Defines Endoplasmic Reticulum Exit Sites and is Required for Secretory Cargo Export in Mammalian CellsTraffic, 2006
- Overexpression of theArabidopsisSyntaxin PEP12/SYP21 Inhibits Transport from the Prevacuolar Compartment to the Lytic Vacuole in VivoTHE PLANT CELL ONLINE, 2006
- Coatomer is essential for retrieval of dilysine-tagged proteins to the endoplasmic reticulumCell, 1994