RESUMO
BACKGROUND: The LYP tyrosine phosphatase presents a SNP (1858C > T) that increases the risk of developing autoimmune diseases such as type I diabetes and arthritis. It remains unclear how this SNP affects LYP function and promotes the development of these diseases. The scarce information about LYP substrates is in part responsible for the poor understanding of LYP function. RESULTS: In this study, we identify in T lymphocytes several adaptor proteins as potential substrates targeted by LYP, including FYB, SLP-76, HS-1, Vav, SKAP1 and SKAP2. We also show that LYP co-localizes with SLP76 in microclusters, upon TCR engagement. CONCLUSIONS: These data indicate that LYP may modulate T cell activation by dephosphorylating several adaptor proteins, such as FYB, SLP-76, HS-1, Vav, SKAP1 and SKAP2 upon TCR engagement.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal , Fosfoproteínas , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária , Linfócitos T , Humanos , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Células Jurkat , Ativação Linfocitária , Fosfoproteínas/metabolismo , Fosforilação , Proteínas Tirosina Fosfatases/metabolismo , Receptores de Antígenos de Linfócitos T/metabolismo , Linfócitos T/metabolismo , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/genética , Proteína Associada à Molécula de Sinalização da Ativação Linfocitária/metabolismoRESUMO
Colorectal Cancer (CRC) therapy confronts challenges as chemoresistance and side effects. Therefore, drugs with antitumor properties that downmodulate aggressiveness mediators are required. Studies have shown the relevance of Low Molecular Weight Protein Tyrosine Phosphatase (LMWPTP), Protein Tyrosine Phosphatase 1B (PTP1B), and Transforming Growth Factor ß (TGFß) in mediating proliferation, chemoresistance, and metastasis. In this study, we aimed to investigate the responsiveness of colorectal cancer lines (HT29 and HCT116) towards Vemurafenib and whether this treatment could modulate these aggressiveness mediators. Cytotoxicity Assays (MTT and Trypan Exclusion Test) were performed to evaluate the viability of HT29 and HCT116 cells treated with Vemurafenib. Western blotting was performed to analyze the amount and/or the activity of mediators (LMWPTP, PTP1B, TGFß, SMAD3), and the immunoprecipitation was performed to evaluate LMWPTP activity. This study brought up novel aspects of Vemurafenib action in colorectal cancer, which can decrease the activity of protein tyrosine phosphatases (LMWPTP and PTP1B) and the TGFß pathway, making them important in the CRC aggressiveness. By downmodulating colorectal cancer hallmarks, Vemurafenib appears as an interesting candidate for CRC therapeutic protocols.
Assuntos
Antineoplásicos/farmacologia , Neoplasias Colorretais/tratamento farmacológico , Proteína Tirosina Fosfatase não Receptora Tipo 1/metabolismo , Proteínas Tirosina Fosfatases/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Fator de Crescimento Transformador beta/metabolismo , Vemurafenib/farmacologia , Neoplasias Colorretais/enzimologia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Células HCT116 , Células HT29 , Humanos , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidores , Proteínas Tirosina Fosfatases/antagonistas & inibidores , Proteínas Proto-Oncogênicas/antagonistas & inibidores , Proteína Smad3/antagonistas & inibidores , Proteína Smad3/metabolismo , Fator de Crescimento Transformador beta/antagonistas & inibidoresRESUMO
Protein tyrosine phosphatases have long been considered key regulators of biological processes and are therefore implicated in the origins of various human diseases. Heterozygosity, mutations, deletions, and the complete loss of some of these enzymes have been reported to cause neurodegenerative diseases, autoimmune syndromes, genetic disorders, metabolic diseases, cancers, and many other physiological imbalances. Vaccinia H1-related phosphatase, also known as dual-specificity phosphatase 3, is a protein tyrosine phosphatase enzyme that regulates the phosphorylation of the mitogen-activated protein kinase signaling pathway, a central mediator of a diversity of biological responses. It has been suggested that vaccinia H1-related phosphatase can act as a tumor suppressor or tumor-promoting phosphatase in different cancers. Furthermore, emerging evidence suggests that this enzyme has many other biological functions, such as roles in immune responses, thrombosis, hemostasis, angiogenesis, and genomic stability, and this broad spectrum of vaccinia H1-related phosphatase activity is likely the result of its diversity of substrates. Hence, fully identifying and characterizing these substrate-phosphatase interactions will facilitate the identification of pharmacological inhibitors of vaccinia H1-related phosphatase that can be evaluated in clinical trials. In this review, we describe the biological processes mediated by vaccinia H1-related phosphatase, especially those related to genomic stability. We also focus on validated substrates and signaling circuitry with clinical relevance in human diseases, particularly oncogenesis.