<italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc

ABSTRACT Manipulation of the host cell is a crucial part of life for many intracellular organisms. We have recently come to appreciate the extent to which the intracellular pathogen Toxoplasma gondii reprograms its host cell, and this is illustrated by the marked upregulation of the central regulato...

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Autores principales:	Michael W. Panas, John C. Boothroyd
Formato:	article
Lenguaje:	EN
Publicado:	American Society for Microbiology 2020
Materias:	GRA16 c-Myc effector protein host-microbial interaction Microbiology QR1-502
Acceso en línea:	https://doaj.org/article/7a6c274a0fac4f598d1cfe1ea0ef747f
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spelling	oai:doaj.org-article:7a6c274a0fac4f598d1cfe1ea0ef747f2021-11-15T15:30:16Z<italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc10.1128/mSphere.00402-202379-5042https://doaj.org/article/7a6c274a0fac4f598d1cfe1ea0ef747f2020-06-01T00:00:00Zhttps://journals.asm.org/doi/10.1128/mSphere.00402-20https://doaj.org/toc/2379-5042ABSTRACT Manipulation of the host cell is a crucial part of life for many intracellular organisms. We have recently come to appreciate the extent to which the intracellular pathogen Toxoplasma gondii reprograms its host cell, and this is illustrated by the marked upregulation of the central regulator c-Myc, an oncogene that coordinates myriad cellular functions. In an effort to identify an effector protein capable of regulating c-Myc, our laboratory constructed a screen for mutant parasites unable to accomplish this upregulation. Interestingly, this screen identified numerous components of a complex located in/on the parasitophorous vacuole membrane necessary to translocate Toxoplasma proteins out into the host cytosol, but it never identified a specific effector protein. Thus, how the parasite upregulates c-Myc has largely been a mystery. Previously, the Toxoplasma dense granule protein GRA16 has been described to bind to one isoform of PP2A-B, a regulatory subunit that coordinates the activity of the catalytic protein phosphatase PP2A. As other PP2A subunits have been reported to target PP2A protein phosphatase activity to c-Myc, subsequently leading to c-Myc destabilization, we examined whether GRA16 has an impact on host c-Myc accumulation. Expression of Toxoplasma’s GRA16 protein in Neospora caninum, a close relative of Toxoplasma that does not naturally upregulate host c-Myc, conferred the ability on Neospora to do this now. Further support was obtained by deleting the GRA16 gene from Toxoplasma and observing a severely diminished ability of Toxoplasma tachyzoites to upregulate host c-Myc. Thus, GRA16 is an effector protein central to Toxoplasma’s ability to upregulate host c-Myc. IMPORTANCE The proto-oncogene c-Myc plays a crucial role in the growth and division of many animal cells. Previous studies have identified an active upregulation of c-Myc by Toxoplasma tachyzoites, suggesting the existence of one or more exported “effector” proteins. The identity of such an effector, however, has not previously been known. Here, we show that a previously known secreted protein, GRA16, plays a crucial role in c-Myc upregulation. This finding will enable further dissection of the precise mechanism and role of c-Myc upregulation in Toxoplasma-infected cells.Michael W. PanasJohn C. BoothroydAmerican Society for MicrobiologyarticleGRA16c-Myceffector proteinhost-microbial interactionMicrobiologyQR1-502ENmSphere, Vol 5, Iss 3 (2020)
institution	DOAJ
collection	DOAJ
language	EN
topic	GRA16 c-Myc effector protein host-microbial interaction Microbiology QR1-502
spellingShingle	GRA16 c-Myc effector protein host-microbial interaction Microbiology QR1-502 Michael W. Panas John C. Boothroyd <italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc
description	ABSTRACT Manipulation of the host cell is a crucial part of life for many intracellular organisms. We have recently come to appreciate the extent to which the intracellular pathogen Toxoplasma gondii reprograms its host cell, and this is illustrated by the marked upregulation of the central regulator c-Myc, an oncogene that coordinates myriad cellular functions. In an effort to identify an effector protein capable of regulating c-Myc, our laboratory constructed a screen for mutant parasites unable to accomplish this upregulation. Interestingly, this screen identified numerous components of a complex located in/on the parasitophorous vacuole membrane necessary to translocate Toxoplasma proteins out into the host cytosol, but it never identified a specific effector protein. Thus, how the parasite upregulates c-Myc has largely been a mystery. Previously, the Toxoplasma dense granule protein GRA16 has been described to bind to one isoform of PP2A-B, a regulatory subunit that coordinates the activity of the catalytic protein phosphatase PP2A. As other PP2A subunits have been reported to target PP2A protein phosphatase activity to c-Myc, subsequently leading to c-Myc destabilization, we examined whether GRA16 has an impact on host c-Myc accumulation. Expression of Toxoplasma’s GRA16 protein in Neospora caninum, a close relative of Toxoplasma that does not naturally upregulate host c-Myc, conferred the ability on Neospora to do this now. Further support was obtained by deleting the GRA16 gene from Toxoplasma and observing a severely diminished ability of Toxoplasma tachyzoites to upregulate host c-Myc. Thus, GRA16 is an effector protein central to Toxoplasma’s ability to upregulate host c-Myc. IMPORTANCE The proto-oncogene c-Myc plays a crucial role in the growth and division of many animal cells. Previous studies have identified an active upregulation of c-Myc by Toxoplasma tachyzoites, suggesting the existence of one or more exported “effector” proteins. The identity of such an effector, however, has not previously been known. Here, we show that a previously known secreted protein, GRA16, plays a crucial role in c-Myc upregulation. This finding will enable further dissection of the precise mechanism and role of c-Myc upregulation in Toxoplasma-infected cells.
format	article
author	Michael W. Panas John C. Boothroyd
author_facet	Michael W. Panas John C. Boothroyd
author_sort	Michael W. Panas
title	<italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc
title_short	<italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc
title_full	<italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc
title_fullStr	<italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc
title_full_unstemmed	<italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc
title_sort	<italic toggle="yes">toxoplasma</italic> uses gra16 to upregulate host c-myc
publisher	American Society for Microbiology
publishDate	2020
url	https://doaj.org/article/7a6c274a0fac4f598d1cfe1ea0ef747f
work_keys_str_mv	AT michaelwpanas italictoggleyestoxoplasmaitalicusesgra16toupregulatehostcmyc AT johncboothroyd italictoggleyestoxoplasmaitalicusesgra16toupregulatehostcmyc
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<italic toggle="yes">Toxoplasma</italic> Uses GRA16 To Upregulate Host c-Myc

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