Identification of PGAM5 as a Mammalian Protein Histidine Phosphatase that Plays a Central Role to Negatively Regulate CD4+ T Cells

• Published in: Molecular cell 2016-08, Vol.63 (3), p.457-469
• Main Authors: Panda, Saswati, Srivastava, Shekhar, Li, Zhai, Vaeth, Martin, Fuhs, Stephen R., Hunter, Tony, Skolnik, Edward Y.
• Format: Article
• Language: English
• Subjects: Animals; calcium; Calcium Signaling; CD4-positive T-lymphocytes; CD4-Positive T-Lymphocytes - enzymology; CD4-Positive T-Lymphocytes - immunology; cytokines; Cytokines - metabolism; Genetic Predisposition to Disease; Graft vs Host Disease - enzymology; Graft vs Host Disease - genetics; Graft vs Host Disease - immunology; HEK293 Cells; Hematopoietic Stem Cell Transplantation - adverse effects; Histidine; histidine phosphorylation; Humans; Inflammation Mediators - metabolism; Intermediate-Conductance Calcium-Activated Potassium Channels - metabolism; Jurkat Cells; Lymphocyte Activation; mammals; Mice, Inbred BALB C; Mice, Inbred C57BL; Mice, Knockout; Mitochondrial Proteins - genetics; Mitochondrial Proteins - metabolism; monoclonal antibodies; nucleoside-diphosphate kinase; Nucleoside-Diphosphate Kinase - metabolism; PGAM5; Phenotype; Phosphoprotein Phosphatases - deficiency; Phosphoprotein Phosphatases - genetics; Phosphoprotein Phosphatases - metabolism; Phosphorylation; potassium channels; protein histidine phosphatases; Receptors, Antigen, T-Cell - metabolism; RNA Interference; serine; T cell activation; threonine; Time Factors; Transfection; tyrosine
• ISSN: 1097-2765; 1097-4164
• DOI: 10.1016/j.molcel.2016.06.021

Whereas phosphorylation of serine, threonine, and tyrosine is exceedingly well characterized, the role of histidine phosphorylation in mammalian signaling is largely unexplored. Here we show that phosphoglycerate mutase family 5 (PGAM5) functions as a phosphohistidine phosphatase that specifically associates with and dephosphorylates the catalytic histidine on nucleoside diphosphate kinase B (NDPK-B). By dephosphorylating NDPK-B, PGAM5 negatively regulates CD4+ T cells by inhibiting NDPK-B-mediated histidine phosphorylation and activation of the K+ channel KCa3.1, which is required for TCR-stimulated Ca2+ influx and cytokine production. Using recently developed monoclonal antibodies that specifically recognize phosphorylation of nitrogens at the N1 (1-pHis) or N3 (3-pHis) positions of the imidazole ring, we detect for the first time phosphoisoform-specific regulation of histidine-phosphorylated proteins in vivo, and we link these modifications to TCR signaling. These results represent an important step forward in studying the role of histidine phosphorylation in mammalian biology and disease. [Display omitted] •PGAM5 is a mammalian histidine phosphatase that specifically dephosphorylates NDPK-B•pHis antibodies detect NDPK-B and KCa3.1 phosphorylation in vitro and in vivo•PGAM5 decreases KCa3.1 activity, Ca2+ influx, and cytokine production in CD4+ T cells•Pgam5−/− T cells cause accelerated and more severe GvHD in mice Protein histidine phosphorylation in mammals has been poorly defined. Panda et al. identify phosphoglycerate mutase 5 (PGAM5) as a mammalian histidine phosphatase that specifically dephosphorylates NDPK-B on H118, thereby inhibiting 3-pHis phosphorylation and activation of the K+ channel KCa3.1. By inhibiting KCa3.1 channel activation, PGAM5 functions to negatively regulate TCR-stimulated Ca2+ influx and pro-inflammatory cytokine production in CD4+ T cells.