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Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression

In Trypanosoma brucei the GPI-anchored variant surface glycoprotein (VSG) represents ∼90% of cell surface protein and a major proportion of endoplasmic reticulum (ER) biosynthetic output. We identified four trypanosomatid-specific genes encoding candidate ER-resident proteins; all were required for...

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Detalles Bibliográficos
Autores principales: Wang, Ya-Nan, Wang, Ming, Field, Mark C.
Formato: Texto
Lenguaje:English
Publicado: Academic Press 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2877885/
https://www.ncbi.nlm.nih.gov/pubmed/20109450
http://dx.doi.org/10.1016/j.exppara.2010.01.015
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author Wang, Ya-Nan
Wang, Ming
Field, Mark C.
author_facet Wang, Ya-Nan
Wang, Ming
Field, Mark C.
author_sort Wang, Ya-Nan
collection PubMed
description In Trypanosoma brucei the GPI-anchored variant surface glycoprotein (VSG) represents ∼90% of cell surface protein and a major proportion of endoplasmic reticulum (ER) biosynthetic output. We identified four trypanosomatid-specific genes encoding candidate ER-resident proteins; all were required for normal proliferation. For Tb11.01.2640 and Tb11.01.8120, an increase in VSG abundance was found on silencing, while the protein products localized to the ER; we designated these ERAP32 and ERAP18 for ER-associated protein of 32 kDa and 18 kDa. Silencing ERAP32 or ERAP18 did not alter expression levels of ISG65 or ISG75, the major surface trans-membrane domain proteins. Surface biotinylation or immunoflorescence did not identify intracellular VSG accumulation, while FACS and fluorescence microscopy indicated that the cells were not increased in size, arguing for increased VSG density on the cell surface. Therefore, ERAP32 and ERAP18 are trypanosome-specific ER-localized proteins with a major role in VSG protein export and, contrary to current paradigms, VSG is not saturated on the cell surface.
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spelling pubmed-28778852010-06-10 Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression Wang, Ya-Nan Wang, Ming Field, Mark C. Exp Parasitol Article In Trypanosoma brucei the GPI-anchored variant surface glycoprotein (VSG) represents ∼90% of cell surface protein and a major proportion of endoplasmic reticulum (ER) biosynthetic output. We identified four trypanosomatid-specific genes encoding candidate ER-resident proteins; all were required for normal proliferation. For Tb11.01.2640 and Tb11.01.8120, an increase in VSG abundance was found on silencing, while the protein products localized to the ER; we designated these ERAP32 and ERAP18 for ER-associated protein of 32 kDa and 18 kDa. Silencing ERAP32 or ERAP18 did not alter expression levels of ISG65 or ISG75, the major surface trans-membrane domain proteins. Surface biotinylation or immunoflorescence did not identify intracellular VSG accumulation, while FACS and fluorescence microscopy indicated that the cells were not increased in size, arguing for increased VSG density on the cell surface. Therefore, ERAP32 and ERAP18 are trypanosome-specific ER-localized proteins with a major role in VSG protein export and, contrary to current paradigms, VSG is not saturated on the cell surface. Academic Press 2010-07 /pmc/articles/PMC2877885/ /pubmed/20109450 http://dx.doi.org/10.1016/j.exppara.2010.01.015 Text en © 2010 Elsevier Inc. https://creativecommons.org/licenses/by/3.0/ Open Access under CC BY 3.0 (https://creativecommons.org/licenses/by/3.0/) license
spellingShingle Article
Wang, Ya-Nan
Wang, Ming
Field, Mark C.
Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression
title Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression
title_full Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression
title_fullStr Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression
title_full_unstemmed Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression
title_short Trypanosoma brucei: Trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression
title_sort trypanosoma brucei: trypanosome-specific endoplasmic reticulum proteins involved in variant surface glycoprotein expression
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2877885/
https://www.ncbi.nlm.nih.gov/pubmed/20109450
http://dx.doi.org/10.1016/j.exppara.2010.01.015
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