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Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection
The intracellular parasite Toxoplasma gondii resides within a membrane-bound parasitophorous vacuole (PV) and secretes an array of proteins to establish this replicative niche. It has been shown previously that Toxoplasma secretes kinases and that numerous proteins are phosphorylated after secretion...
Autores principales: | , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Microbiology
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7485689/ https://www.ncbi.nlm.nih.gov/pubmed/32907954 http://dx.doi.org/10.1128/mSphere.00792-20 |
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author | Young, Joanna C. Broncel, Malgorzata Teague, Helena Russell, Matt R. G. McGovern, Olivia L. Renshaw, Matt Frith, David Snijders, Ambrosius P. Collinson, Lucy Carruthers, Vern B. Ewald, Sarah E. Treeck, Moritz |
author_facet | Young, Joanna C. Broncel, Malgorzata Teague, Helena Russell, Matt R. G. McGovern, Olivia L. Renshaw, Matt Frith, David Snijders, Ambrosius P. Collinson, Lucy Carruthers, Vern B. Ewald, Sarah E. Treeck, Moritz |
author_sort | Young, Joanna C. |
collection | PubMed |
description | The intracellular parasite Toxoplasma gondii resides within a membrane-bound parasitophorous vacuole (PV) and secretes an array of proteins to establish this replicative niche. It has been shown previously that Toxoplasma secretes kinases and that numerous proteins are phosphorylated after secretion. Here, we assess the role of the phosphorylation of strand-forming protein 1 (SFP1) and the related protein GRA29, two secreted proteins with unknown function. We show that both proteins form stranded structures in the PV that are independent of the previously described intravacuolar network or actin. SFP1 and GRA29 can each form these structures independently of other Toxoplasma secreted proteins, although GRA29 appears to regulate SFP1 strands. We show that an unstructured region at the C termini of SFP1 and GRA29 is required for the formation of strands and that mimicking the phosphorylation of this domain of SFP1 negatively regulates strand development. When tachyzoites convert to chronic-stage bradyzoites, both proteins show a dispersed localization throughout the cyst matrix. Many secreted proteins are reported to dynamically redistribute as the cyst forms, and secreted kinases are known to play a role in cyst formation. Using quantitative phosphoproteome and proteome analyses comparing tachyzoite and early bradyzoite stages, we reveal widespread differential phosphorylation of secreted proteins. While we found no direct evidence for phosphorylation playing a dominant role for SFP1/GRA29 redistribution in the cyst, these data support a model in which secreted kinases and phosphatases contribute to the regulation of secreted proteins during stage conversion. IMPORTANCE Toxoplasma gondii is a common parasite that infects up to one-third of the human population. Initially, the parasite grows rapidly, infecting and destroying cells of the host, but subsequently switches to a slow-growing form and establishes chronic infection. In both stages, the parasite lives within a membrane-bound vacuole within the host cell, but in the chronic stage, a durable cyst wall is synthesized, which provides protection to the parasite during transmission to a new host. Toxoplasma secretes proteins into the vacuole to build its replicative niche, and previous studies identified many of these proteins as phosphorylated. We investigate two secreted proteins and show that a phosphorylated region plays an important role in their regulation in acute stages. We also observed widespread phosphorylation of secreted proteins when parasites convert from acute to chronic stages, providing new insight into how the cyst wall may be dynamically regulated. |
format | Online Article Text |
id | pubmed-7485689 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | American Society for Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-74856892020-09-15 Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection Young, Joanna C. Broncel, Malgorzata Teague, Helena Russell, Matt R. G. McGovern, Olivia L. Renshaw, Matt Frith, David Snijders, Ambrosius P. Collinson, Lucy Carruthers, Vern B. Ewald, Sarah E. Treeck, Moritz mSphere Research Article The intracellular parasite Toxoplasma gondii resides within a membrane-bound parasitophorous vacuole (PV) and secretes an array of proteins to establish this replicative niche. It has been shown previously that Toxoplasma secretes kinases and that numerous proteins are phosphorylated after secretion. Here, we assess the role of the phosphorylation of strand-forming protein 1 (SFP1) and the related protein GRA29, two secreted proteins with unknown function. We show that both proteins form stranded structures in the PV that are independent of the previously described intravacuolar network or actin. SFP1 and GRA29 can each form these structures independently of other Toxoplasma secreted proteins, although GRA29 appears to regulate SFP1 strands. We show that an unstructured region at the C termini of SFP1 and GRA29 is required for the formation of strands and that mimicking the phosphorylation of this domain of SFP1 negatively regulates strand development. When tachyzoites convert to chronic-stage bradyzoites, both proteins show a dispersed localization throughout the cyst matrix. Many secreted proteins are reported to dynamically redistribute as the cyst forms, and secreted kinases are known to play a role in cyst formation. Using quantitative phosphoproteome and proteome analyses comparing tachyzoite and early bradyzoite stages, we reveal widespread differential phosphorylation of secreted proteins. While we found no direct evidence for phosphorylation playing a dominant role for SFP1/GRA29 redistribution in the cyst, these data support a model in which secreted kinases and phosphatases contribute to the regulation of secreted proteins during stage conversion. IMPORTANCE Toxoplasma gondii is a common parasite that infects up to one-third of the human population. Initially, the parasite grows rapidly, infecting and destroying cells of the host, but subsequently switches to a slow-growing form and establishes chronic infection. In both stages, the parasite lives within a membrane-bound vacuole within the host cell, but in the chronic stage, a durable cyst wall is synthesized, which provides protection to the parasite during transmission to a new host. Toxoplasma secretes proteins into the vacuole to build its replicative niche, and previous studies identified many of these proteins as phosphorylated. We investigate two secreted proteins and show that a phosphorylated region plays an important role in their regulation in acute stages. We also observed widespread phosphorylation of secreted proteins when parasites convert from acute to chronic stages, providing new insight into how the cyst wall may be dynamically regulated. American Society for Microbiology 2020-09-09 /pmc/articles/PMC7485689/ /pubmed/32907954 http://dx.doi.org/10.1128/mSphere.00792-20 Text en © Crown copyright 2020. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Research Article Young, Joanna C. Broncel, Malgorzata Teague, Helena Russell, Matt R. G. McGovern, Olivia L. Renshaw, Matt Frith, David Snijders, Ambrosius P. Collinson, Lucy Carruthers, Vern B. Ewald, Sarah E. Treeck, Moritz Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection |
title | Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection |
title_full | Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection |
title_fullStr | Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection |
title_full_unstemmed | Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection |
title_short | Phosphorylation of Toxoplasma gondii Secreted Proteins during Acute and Chronic Stages of Infection |
title_sort | phosphorylation of toxoplasma gondii secreted proteins during acute and chronic stages of infection |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7485689/ https://www.ncbi.nlm.nih.gov/pubmed/32907954 http://dx.doi.org/10.1128/mSphere.00792-20 |
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