Academic Journal
GPI valence and the fate of secretory membrane proteins in African trypanosomes
| العنوان: | GPI valence and the fate of secretory membrane proteins in African trypanosomes |
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| المؤلفون: | Schwartz, Kevin J., Peck, Ronald F., Tazeh, Ngii N., Bangs, James D. |
| بيانات النشر: | Company of Biologists |
| سنة النشر: | 2005 |
| المجموعة: | HighWire Press (Stanford University) |
| مصطلحات موضوعية: | Research Article |
| الوصف: | Progression of GPI-anchored proteins in bloodstream African trypanosomes correlates with GPI-valence: homodimeric VSG (2 GPI) is a surface protein; heterodimeric transferrin receptor (1 GPI) localizes in the flagellar pocket; homodimeric GPI-minus VSG (0 GPI) is rapidly degraded in the lysosome. We test this relationship using three native secretory/endocytic proteins as monomeric GPI-plus and -minus reporters. GPI-minus procyclin trafficks to the lysosome and is degraded. GPI-plus procyclin trafficks to the flagellar pocket/cell surface and is released (∼50%) with an intact anchor, the remainder (∼50%) is degraded in the lysosome. GPI-plus BiPNHP, derived from the ER marker BiP, is released quantitatively (>80%), while GPI-plus p67HP, derived from the lysosomal marker p67, turns over by both release (∼15%) and lysosomal degradation (>50%). Turnover of endogenous transferrin receptor occurs primarily by lysosomal degradation (>90%). Thus shedding of monovalent GPI reporters correlates inversely with lysosomal targeting. We propose that mono-GPI reporters cycle through the flagellar pocket and endosome until they are disposed of by either shedding or lysosomal targeting. Partitioning between these fates may be a function of individual physical properties. Release is likely due to the exclusive use of C-14:0 myristate in the bloodstream stage GPI anchor. Up-regulation of transferrin receptor by culture in dog serum resulted in prominent cell surface localization, but not in elevated release. Surface receptor was non-functional for ligand binding suggesting that it may be bivalent homodimers of the GPI-anchored ESAG6 receptor subunit. |
| نوع الوثيقة: | text |
| وصف الملف: | text/html |
| اللغة: | English |
| Relation: | http://jcs.biologists.org/cgi/content/short/118/23/5499; http://dx.doi.org/10.1242/jcs.02667 |
| DOI: | 10.1242/jcs.02667 |
| الاتاحة: | http://jcs.biologists.org/cgi/content/short/118/23/5499 https://doi.org/10.1242/jcs.02667 |
| Rights: | Copyright (C) 2005, Company of Biologists |
| رقم الانضمام: | edsbas.9F45EDC3 |
| قاعدة البيانات: | BASE |
| DOI: | 10.1242/jcs.02667 |
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