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Constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (LPAP)
Lymphocyte phosphatase-associated phosphoprotein (LPAP) is a small transmembrane protein expressed exclusively in lymphocytes. LPAP is a component of a supramolecular complex composed of the phosphatase CD45, the co-receptor CD4, and the kinase Lck. In contrast to its immunologically important partn...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2017
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5565103/ https://www.ncbi.nlm.nih.gov/pubmed/28827793 http://dx.doi.org/10.1371/journal.pone.0182468 |
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author | Kruglova, Natalia A. Meshkova, Tatiana D. Kopylov, Arthur T. Mazurov, Dmitriy V. Filatov, Alexander V. |
author_facet | Kruglova, Natalia A. Meshkova, Tatiana D. Kopylov, Arthur T. Mazurov, Dmitriy V. Filatov, Alexander V. |
author_sort | Kruglova, Natalia A. |
collection | PubMed |
description | Lymphocyte phosphatase-associated phosphoprotein (LPAP) is a small transmembrane protein expressed exclusively in lymphocytes. LPAP is a component of a supramolecular complex composed of the phosphatase CD45, the co-receptor CD4, and the kinase Lck. In contrast to its immunologically important partners, the function of LPAP is unknown. We hypothesized that the biological role of LPAP may be determined by analyzing LPAP phosphorylation. In the present study, we identified LPAP phosphorylation sites by site-directed mutagenesis, phospho-specific antibodies, and protein immunoprecipitation coupled to mass spectrometry analysis. Our results confirmed previous reports that Ser-99, Ser-153, and Ser-163 are phosphorylated, as well as provided evidence for the phosphorylation of Ser-172. Using various SDS-PAGE techniques, we detected and quantified a set of LPAP phosphoforms that were assigned to a combination of particular phosphorylation events. The phosphorylation of LPAP appears to be a tightly regulated process. Our results support the model: following phorbol 12-myristate 13-acetate (PMA) or TCR/CD3 activation of T cells, LPAP is rapidly dephosphorylated at Ser-99 and Ser-172 and slowly phosphorylated at Ser-163. Ser-153 exhibited a high basal level of phosphorylation in both resting and activated cells. Therefore, we suggest that LPAP may function as a co-regulator of T-cell signaling. |
format | Online Article Text |
id | pubmed-5565103 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2017 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-55651032017-08-28 Constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (LPAP) Kruglova, Natalia A. Meshkova, Tatiana D. Kopylov, Arthur T. Mazurov, Dmitriy V. Filatov, Alexander V. PLoS One Research Article Lymphocyte phosphatase-associated phosphoprotein (LPAP) is a small transmembrane protein expressed exclusively in lymphocytes. LPAP is a component of a supramolecular complex composed of the phosphatase CD45, the co-receptor CD4, and the kinase Lck. In contrast to its immunologically important partners, the function of LPAP is unknown. We hypothesized that the biological role of LPAP may be determined by analyzing LPAP phosphorylation. In the present study, we identified LPAP phosphorylation sites by site-directed mutagenesis, phospho-specific antibodies, and protein immunoprecipitation coupled to mass spectrometry analysis. Our results confirmed previous reports that Ser-99, Ser-153, and Ser-163 are phosphorylated, as well as provided evidence for the phosphorylation of Ser-172. Using various SDS-PAGE techniques, we detected and quantified a set of LPAP phosphoforms that were assigned to a combination of particular phosphorylation events. The phosphorylation of LPAP appears to be a tightly regulated process. Our results support the model: following phorbol 12-myristate 13-acetate (PMA) or TCR/CD3 activation of T cells, LPAP is rapidly dephosphorylated at Ser-99 and Ser-172 and slowly phosphorylated at Ser-163. Ser-153 exhibited a high basal level of phosphorylation in both resting and activated cells. Therefore, we suggest that LPAP may function as a co-regulator of T-cell signaling. Public Library of Science 2017-08-21 /pmc/articles/PMC5565103/ /pubmed/28827793 http://dx.doi.org/10.1371/journal.pone.0182468 Text en © 2017 Kruglova et al http://creativecommons.org/licenses/by/4.0/ This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. |
spellingShingle | Research Article Kruglova, Natalia A. Meshkova, Tatiana D. Kopylov, Arthur T. Mazurov, Dmitriy V. Filatov, Alexander V. Constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (LPAP) |
title | Constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (LPAP) |
title_full | Constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (LPAP) |
title_fullStr | Constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (LPAP) |
title_full_unstemmed | Constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (LPAP) |
title_short | Constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (LPAP) |
title_sort | constitutive and activation-dependent phosphorylation of lymphocyte phosphatase-associated phosphoprotein (lpap) |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5565103/ https://www.ncbi.nlm.nih.gov/pubmed/28827793 http://dx.doi.org/10.1371/journal.pone.0182468 |
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