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Ehrlichia chaffeensis TRP32 Nucleomodulin Function and Localization Is Regulated by NEDD4L-Mediated Ubiquitination

Ehrlichia chaffeensis is an obligately intracellular bacterium that reprograms the mononuclear phagocyte through diverse effector-host interactions to modulate various host cell processes. In a previous study, we reported that the E. chaffeensis nucleomodulin TRP32 regulates transcription of host ge...

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Autores principales: Farris, Tierra R., Zhu, Bing, Wang, Jennifer Y., McBride, Jere W.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Frontiers Media S.A. 2018
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5768648/
https://www.ncbi.nlm.nih.gov/pubmed/29376035
http://dx.doi.org/10.3389/fcimb.2017.00534
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author Farris, Tierra R.
Zhu, Bing
Wang, Jennifer Y.
McBride, Jere W.
author_facet Farris, Tierra R.
Zhu, Bing
Wang, Jennifer Y.
McBride, Jere W.
author_sort Farris, Tierra R.
collection PubMed
description Ehrlichia chaffeensis is an obligately intracellular bacterium that reprograms the mononuclear phagocyte through diverse effector-host interactions to modulate various host cell processes. In a previous study, we reported that the E. chaffeensis nucleomodulin TRP32 regulates transcription of host genes in several biologically relevant categories, including cell differentiation and proliferation. In this study, we investigate the effect of ubiquitination on TRP32 function and localization within the host cell. TRP32 is both mono- and polyubiquitinated on multiple lysine residues during infection and when ectopically expressed. Despite lacking a canonical PPxY motif, TRP32 interacted with, and was modified by the human HECT E3 ubiquitin (Ub) ligase NEDD4L. TRP32 ubiquitination was not by K48-linked polyUb chains, nor was it degraded by the proteasome; however, TRP32 was modified by K63-linked polyUb chains detected both in the cytosol and nucleus. HECT ligase inhibitor, heclin, altered the subnuclear localization of ectopically expressed TRP32 from a diffuse nuclear pattern to a lacy, punctate pattern with TRP32 distributed around the periphery of the nucleus and nucleoli. When a TRP32 lysine null (K-null) mutant was ectopically expressed, it exhibited a similar phenotype as single lysine mutants (K63R, K93R, and K123R). However, the K-null mutant showed increased amounts of cytoplasmic TRP32 compared to single lysine mutants or heclin-treated cells ectopically expressing TRP32. These alterations in localization corresponded to changes in TRP32 transcriptional repressor function with heclin-treated and single lysine mutants unable to repress transcription of a TRP32 target genes in a luciferase assay.
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spelling pubmed-57686482018-01-26 Ehrlichia chaffeensis TRP32 Nucleomodulin Function and Localization Is Regulated by NEDD4L-Mediated Ubiquitination Farris, Tierra R. Zhu, Bing Wang, Jennifer Y. McBride, Jere W. Front Cell Infect Microbiol Microbiology Ehrlichia chaffeensis is an obligately intracellular bacterium that reprograms the mononuclear phagocyte through diverse effector-host interactions to modulate various host cell processes. In a previous study, we reported that the E. chaffeensis nucleomodulin TRP32 regulates transcription of host genes in several biologically relevant categories, including cell differentiation and proliferation. In this study, we investigate the effect of ubiquitination on TRP32 function and localization within the host cell. TRP32 is both mono- and polyubiquitinated on multiple lysine residues during infection and when ectopically expressed. Despite lacking a canonical PPxY motif, TRP32 interacted with, and was modified by the human HECT E3 ubiquitin (Ub) ligase NEDD4L. TRP32 ubiquitination was not by K48-linked polyUb chains, nor was it degraded by the proteasome; however, TRP32 was modified by K63-linked polyUb chains detected both in the cytosol and nucleus. HECT ligase inhibitor, heclin, altered the subnuclear localization of ectopically expressed TRP32 from a diffuse nuclear pattern to a lacy, punctate pattern with TRP32 distributed around the periphery of the nucleus and nucleoli. When a TRP32 lysine null (K-null) mutant was ectopically expressed, it exhibited a similar phenotype as single lysine mutants (K63R, K93R, and K123R). However, the K-null mutant showed increased amounts of cytoplasmic TRP32 compared to single lysine mutants or heclin-treated cells ectopically expressing TRP32. These alterations in localization corresponded to changes in TRP32 transcriptional repressor function with heclin-treated and single lysine mutants unable to repress transcription of a TRP32 target genes in a luciferase assay. Frontiers Media S.A. 2018-01-11 /pmc/articles/PMC5768648/ /pubmed/29376035 http://dx.doi.org/10.3389/fcimb.2017.00534 Text en Copyright © 2018 Farris, Zhu, Wang and McBride. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
spellingShingle Microbiology
Farris, Tierra R.
Zhu, Bing
Wang, Jennifer Y.
McBride, Jere W.
Ehrlichia chaffeensis TRP32 Nucleomodulin Function and Localization Is Regulated by NEDD4L-Mediated Ubiquitination
title Ehrlichia chaffeensis TRP32 Nucleomodulin Function and Localization Is Regulated by NEDD4L-Mediated Ubiquitination
title_full Ehrlichia chaffeensis TRP32 Nucleomodulin Function and Localization Is Regulated by NEDD4L-Mediated Ubiquitination
title_fullStr Ehrlichia chaffeensis TRP32 Nucleomodulin Function and Localization Is Regulated by NEDD4L-Mediated Ubiquitination
title_full_unstemmed Ehrlichia chaffeensis TRP32 Nucleomodulin Function and Localization Is Regulated by NEDD4L-Mediated Ubiquitination
title_short Ehrlichia chaffeensis TRP32 Nucleomodulin Function and Localization Is Regulated by NEDD4L-Mediated Ubiquitination
title_sort ehrlichia chaffeensis trp32 nucleomodulin function and localization is regulated by nedd4l-mediated ubiquitination
topic Microbiology
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5768648/
https://www.ncbi.nlm.nih.gov/pubmed/29376035
http://dx.doi.org/10.3389/fcimb.2017.00534
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