An unexpected 2-histidine phosphoesterase activity of suppressor of T-cell receptor signaling protein 1 contributes to the suppression of cell signaling
| Autor: | Nick Carpino, Jarrod B. French, David A. Frank, Yue Yin, Weijie Zhou, Neena Kaur |
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| Rok vydání: | 2020 |
| Předmět: |
0301 basic medicine
Cell signaling T-Lymphocytes Amino Acid Motifs Protein domain Phosphatase Receptors Antigen T-Cell Biochemistry SH3 domain Substrate Specificity Interferon-gamma Mice 03 medical and health sciences Cyclic nucleotide chemistry.chemical_compound Catalytic Domain Animals Humans Lectins C-Type Molecular Biology Histidine Mice Knockout 030102 biochemistry & molecular biology T-cell receptor Cell Biology Cell biology Mice Inbred C57BL Kinetics 030104 developmental biology chemistry Mutagenesis Site-Directed Protein Tyrosine Phosphatases Signal transduction Sequence Alignment NADP Signal Transduction |
| Zdroj: | J Biol Chem |
| ISSN: | 0021-9258 |
| Popis: | The suppressor of T-cell receptor (TCR) signaling (Sts) proteins Sts-1 and Sts-2 suppress receptor-mediated signaling pathways in various immune cells, including the TCR pathway in T cells and the Dectin-1 signaling pathway in phagocytes. As multidomain enzymes, they contain an N-terminal ubiquitin-association domain, a central Src homology 3 domain, and a C-terminal histidine phosphatase domain. Recently, a 2-histidine (2H) phosphoesterase motif was identified within the N-terminal portion of Sts. The 2H phosphoesterase motif defines an evolutionarily ancient protein domain present in several enzymes that hydrolyze cyclic phosphate bonds on different substrates, including cyclic nucleotides. It is characterized by two invariant histidine residues that play a critical role in catalytic activity. Consistent with its assignment as a phosphoesterase, we demonstrate here that the Sts-1 2H phosphoesterase domain displays catalytic, saturable phosphodiesterase activity toward the dinucleotide 2',3'-cyclic NADP. The enzyme exhibited a high degree of substrate specificity and selectively generated the 3'-nucleotide as the sole product. Sts-1 also had phosphodiesterase catalytic activity toward a 5-mer RNA oligonucleotide containing a 2',3'-cyclic phosphate group at its 3' terminus. To investigate the functional significance of Sts-1 2H phosphoesterase activity, we generated His-to-Ala variants and examined their ability to negatively regulate cellular signaling pathways. Substitution of either conserved histidine compromised the ability of Sts-1 to suppress signaling pathways downstream of both the TCR and the Dectin-1 receptor. Our results identify a heretofore unknown cellular enzyme activity associated with Sts-1 and indicate that this catalytic activity is linked to specific cell-signaling outcomes. |
| Databáze: | OpenAIRE |
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