Protein delivery to vacuole requires SAND protein-dependent rab GTPase conversion for MVB-vacuole fusion
Summary Plasma-membrane proteins such as ligand-binding receptor kinases, ion channels, or nutrient transporters are turned over by targeting to a lytic compartment—lysosome or vacuole—for degradation. After their internalization, these proteins arrive at an early endosome, which then matures into a...
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| Main Authors: | , |
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| Format: | Article (Journal) |
| Language: | English |
| Published: |
16 June 2014
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| In: |
Current biology
Year: 2014, Volume: 24, Issue: 12, Pages: 1383-1389 |
| ISSN: | 1879-0445 |
| DOI: | 10.1016/j.cub.2014.05.005 |
| Online Access: | Verlag, kostenfrei, Volltext: http://dx.doi.org/10.1016/j.cub.2014.05.005 Verlag, kostenfrei, Volltext: http://www.sciencedirect.com/science/article/pii/S0960982214005302 
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| Author Notes: | Manoj K. Singh, Falco Krüger, Hauke Beckmann, Sabine Brumm, Joop E. M. Vermeer, Teun Munnik, Ulrike Mayer, York-Dieter Stierhof, Christopher Grefen, Karin Schumacher, Gerd Jürgens |
| Summary: | Summary Plasma-membrane proteins such as ligand-binding receptor kinases, ion channels, or nutrient transporters are turned over by targeting to a lytic compartment—lysosome or vacuole—for degradation. After their internalization, these proteins arrive at an early endosome, which then matures into a late endosome with intraluminal vesicles (multivesicular body, MVB) before fusing with the lysosome/vacuole in animals or yeast [1, 2]. The endosomal maturation step involves a SAND family protein mediating Rab5-to-Rab7 GTPase conversion [3]. Vacuolar trafficking is much less well understood in plants [4-6]. Here we analyze the role of the single-copy SAND gene of Arabidopsis. In contrast to its animal or yeast counterpart, Arabidopsis SAND protein is not required for early-to-late endosomal maturation, although its role in mediating Rab5-to-Rab7 conversion is conserved. Instead, Arabidopsis SAND protein is essential for the subsequent fusion of MVBs with the vacuole. The inability of sand mutant to mediate MVB-vacuole fusion is not caused by the continued Rab5 activity but rather reflects the failure to activate Rab7. In conclusion, regarding the endosomal passage of cargo proteins for degradation, a major difference between plants and nonplant organisms might result from the relative timing of endosomal maturation and SAND-dependent Rab GTPase conversion as a prerequisite for the fusion of late endosomes/MVBs with the lysosome/vacuole. |
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| Item Description: | Gesehen am 09.05.2017 |
| Physical Description: | Online Resource |
| ISSN: | 1879-0445 |
| DOI: | 10.1016/j.cub.2014.05.005 |