Critical Roles for Coiled-Coil Dimers of Butyrophilin 3A1 in the Sensing of Prenyl Pyrophosphates by Human Vγ2Vδ2 T Cells
| Autor: | Yoshimasa Tanaka, Craig T. Morita, Mohanad H. Nada, Shun Sakuraba, Hong Wang |
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| Rok vydání: | 2019 |
| Předmět: |
Dimer
Immunology Isopentenyl pyrophosphate B30.2-SPRY Domain CD8-Positive T-Lymphocytes Molecular Dynamics Simulation Lymphocyte Activation medicine.disease_cause Pyrophosphate Article 03 medical and health sciences chemistry.chemical_compound Hemiterpenes Organophosphorus Compounds 0302 clinical medicine Butyrophilin Prenylation Antigens CD medicine Humans Immunology and Allergy Amino Acid Sequence Coiled coil Mutation Butyrophilins Mutagenesis Receptors Antigen T-Cell gamma-delta Organophosphates Amino Acid Substitution chemistry Biophysics Dimerization 030215 immunology |
| Zdroj: | J Immunol |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.1801252 |
| Popis: | Vγ2Vδ2 T cells play important roles in human immunity to pathogens and tumors. Their TCRs respond to the sensing of isoprenoid metabolites, such as (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate and isopentenyl pyrophosphate, by butyrophilin (BTN) 3A1. BTN3A1 is an Ig superfamily protein with extracellular IgV/IgC domains and intracellular B30.2 domains that bind prenyl pyrophosphates. We have proposed that intracellular α helices form a coiled-coil dimer that functions as a spacer for the B30.2 domains. To test this, five pairs of anchor residues were mutated to glycine to destabilize the coiled-coil dimer. Despite maintaining surface expression, BTN3A1 mutagenesis either abrogated or decreased stimulation by (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate. BTN3A2 and BTN3A3 proteins and orthologs in alpacas and dolphins are also predicted to have similar coiled-coil dimers. A second short coiled-coil region dimerizes the B30.2 domains. Molecular dynamics simulations predict that mutation of a conserved tryptophan residue in this region will destabilize the dimer, explaining the loss of stimulation by BTN3A1 proteins with this mutation. The juxtamembrane regions of other BTN/BTN-like proteins with B30.2 domains are similarly predicted to assume α helices, with many predicted to form coiled-coil dimers. An exon at the end of this region and the exon encoding the dimerization region for B30.2 domains are highly conserved. We propose that coiled-coil dimers function as rod-like helical molecular spacers to position B30.2 domains, as interaction sites for other proteins, and as dimerization regions to allow sensing by B30.2 domains. In these ways, the coiled-coil domains of BTN3A1 play critical roles for its function. |
| Databáze: | OpenAIRE |
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