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Peptidoglycan Metabolite Photoaffinity Reporters Reveal Direct Binding to Intracellular Pattern Recognition Receptors and Arf GTPases.

ABSTRACT: The peptidoglycan fragments ?-d-glutamyl- meso-diaminopimelic acid (iE-DAP) and muramyl-dipeptide (MDP) are microbial-specific metabolites that activate intracellular pattern recognition receptors and stimulate immune signaling pathways. While extensive structure-activity studies have demonstrated that these bacterial cell wall metabolites trigger NOD1- and NOD2-dependent signaling, their direct binding to these innate immune receptors or other proteins in mammalian cells has not been established. To characterize these fundamental microbial metabolite-host interactions, we synthesized a series of peptidoglycan metabolite photoaffinity reporters and evaluated their cross-linking to NOD1 and NOD2 in mammalian cells. We show that active iE-DAP and MDP photoaffinity reporters selectively cross-linked NOD1 and NOD2, respectively, and not their inactive mutants. We also discovered MDP reporter cross-linking to Arf GTPases, which interacted most prominently with GTP-bound Arf6 and coimmunoprecipitated with NOD2 upon MDP stimulation. Notably, MDP binding to NOD2 and Arf6 was abrogated with loss-of-function NOD2 mutants associated with Crohn's disease. Our studies demonstrate peptidoglycan metabolite photoaffinity reporters can capture their cognate immune receptors in cells and reveal unpredicted ligand-induced interactions with other cellular cofactors. These photoaffinity reporters should afford useful tools to discover and characterize other peptidoglycan metabolite-interacting proteins.

SUBMITTER: Wang YC

PROVIDER: S-EPMC6943928 | biostudies-literature | 2019 Mar

REPOSITORIES: biostudies-literature

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Peptidoglycan Metabolite Photoaffinity Reporters Reveal Direct Binding to Intracellular Pattern Recognition Receptors and Arf GTPases.

Wang Yen-Chih YC Westcott Nathan P NP Griffin Matthew E ME Hang Howard C HC

ACS chemical biology 20190220 3

The peptidoglycan fragments γ-d-glutamyl- meso-diaminopimelic acid (iE-DAP) and muramyl-dipeptide (MDP) are microbial-specific metabolites that activate intracellular pattern recognition receptors and stimulate immune signaling pathways. While extensive structure-activity studies have demonstrated that these bacterial cell wall metabolites trigger NOD1- and NOD2-dependent signaling, their direct binding to these innate immune receptors or other proteins in mammalian cells has not been establishe ...[more]

PMID: 30735346

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Dataset Information

Peptidoglycan Metabolite Photoaffinity Reporters Reveal Direct Binding to Intracellular Pattern Recognition Receptors and Arf GTPases.

Publications

Peptidoglycan Metabolite Photoaffinity Reporters Reveal Direct Binding to Intracellular Pattern Recognition Receptors and Arf GTPases.

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