Sullivan, Lucy C., Berry, Richard, Sosnin, Natasha, Widjaja, Jacqueline M. L., Deuss, Felix A., Balaji, Gautham R., LaGruta, Nicole L., Mirams, Michiko, Trapani, Joseph A., Rossjohn, Jamie ![]() ![]() |
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Abstract
Murine natural killer (NK) cells are regulated by the interaction of Ly49 receptors with major histocompatibility complex class I molecules (MHC-I). Although the ligands for inhibitory Ly49 were considered to be restricted to classical MHC (MHC-Ia), we have shown that the non-classical MHC molecule (MHC-Ib) H2-M3 was a ligand for the inhibitory Ly49A. Here we establish that another MHC-Ib, H2-Q10, is a bona fide ligand for the inhibitory Ly49C receptor. H2-Q10 bound to Ly49C with a marginally lower affinity (∼5 μm) than that observed between Ly49C and MHC-Ia (H-2Kb/H-2Dd, both ∼1 μm), and this recognition could be prevented by cis interactions with H-2K in situ. To understand the molecular details underpinning Ly49·MHC-Ib recognition, we determined the crystal structures of H2-Q10 and Ly49C bound H2-Q10. Unliganded H2-Q10 adopted a classical MHC-I fold and possessed a peptide-binding groove that exhibited features similar to those found in MHC-Ia, explaining the diverse peptide binding repertoire of H2-Q10. Ly49C bound to H2-Q10 underneath the peptide binding platform to a region that encompassed residues from the α1, α2, and α3 domains, as well as the associated β2-microglobulin subunit. This docking mode was conserved with that previously observed for Ly49C·H-2Kb. Indeed, structure-guided mutation of Ly49C indicated that Ly49C·H2-Q10 and Ly49C·H-2Kb possess similar energetic footprints focused around residues located within the Ly49C β4-stand and L5 loop, which contact the underside of the peptide-binding platform floor. Our data provide a structural basis for Ly49·MHC-Ib recognition and demonstrate that MHC-Ib represent an extended family of ligands for Ly49 molecules.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Medicine |
Subjects: | R Medicine > R Medicine (General) |
Publisher: | American Society for Biochemistry and Molecular Biology |
ISSN: | 0021-9258 |
Date of First Compliant Deposit: | 12 June 2017 |
Date of Acceptance: | 1 July 2016 |
Last Modified: | 05 May 2023 09:10 |
URI: | https://orca.cardiff.ac.uk/id/eprint/100015 |
Citation Data
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