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The butyrophilin 3A1 intracellular domain undergoes a conformational change involving the juxtamembrane region
Author(s) -
Nguyen Khiem,
Li Jin,
Puthenveetil Robbins,
Lin Xiaochen,
Poe Michael M.,
Christine Hsiao ChiaHung,
Vinogradova Olga,
Wiemer Andrew J.
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.201601370rr
Subject(s) - conformational change , chemistry , stereochemistry , intracellular , mutant , ligand (biochemistry) , nuclear magnetic resonance spectroscopy , amide , crystallography , biophysics , receptor , biology , biochemistry , gene
Small isoprenoid diphosphates, such as ( E )‐4‐hydroxy‐3‐methyl‐but‐2‐enyl diphosphate (HMBPP), are ligands of the internal domain of BTN3A1. Ligand binding in target cells promotes activation of Vγ9Vδ2 T cells. We demonstrate by small‐angle X‐ray scattering (SAXS) that HMBPP binding to the internal domain of BTN3A1 induces a conformational change in the position of the B30.2 domain relative to the juxtamembrane (JM) region. To better understand the molecular details of this conformational rearrangement, NMR spectroscopy was used to discover that the JM region interacts with HMBPP, specifically at the diphosphate. The spectral location of the affected amide peaks, partial NMR assignments, and JM mutants (ST 296 AA or T 304 A) investigated, confirm that the backbone amide of at least one Thr (Thr 304 ), adjacent to conserved Ser, comes close to the HMBPP diphosphate, whereas double mutation of nonconserved residues (Ser/Thr 296/297 ) may perturb the local fold. Cellular mutation of either of the identified Thr residues reduces the activation of Vγ9Vδ2 T cells by HMBPP, zoledronate, and POM 2 ‐C‐HMBP, but not by a partial agonist BTN3 antibody. Taken together, our results show that ligand binding to BTN3A1 induces a conformational change within the intracellular domain that involves the JM region and is required for full activation.—Nguyen, K., Li, J., Puthenveetil, R., Lin, X., Poe, M. M., Hsiao, C.‐H. C., Vinogradova, O., Wiemer, A. J. The butyrophilin 3A1 intracellular domain undergoes a conformational change involving the juxtamembrane region. FASEB J. 31, 4697–4706 (2017). www.fasebj.org