5Z2C image
Entry Detail
PDB ID:
5Z2C
Keywords:
Title:
Crystal structure of ALPK-1 N-terminal domain in complex with ADP-heptose
Biological Source:
Source Organism:
PDB Version:
Deposition Date:
2018-01-02
Release Date:
2018-08-22
Method Details:
Experimental Method:
Resolution:
2.59 Å
R-Value Free:
0.26
R-Value Work:
0.24
R-Value Observed:
0.24
Space Group:
C 1 2 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Alpha-protein kinase 1
Chain IDs:A, B, C, D, E, F, G, H, I
Chain Length:446
Number of Molecules:9
Biological Source:Homo sapiens
Ligand Molecules
Primary Citation
Alpha-kinase 1 is a cytosolic innate immune receptor for bacterial ADP-heptose.
Nature 561 122 126 (2018)
PMID: 30111836 DOI: 10.1038/s41586-018-0433-3

Abstact

Immune recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors often activates proinflammatory NF-κB signalling1. Recent studies indicate that the bacterial metabolite D-glycero-β-D-manno-heptose 1,7-bisphosphate (HBP) can activate NF-κB signalling in host cytosol2-4, but it is unclear whether HBP is a genuine PAMP and the cognate pattern recognition receptor has not been identified. Here we combined a transposon screen in Yersinia pseudotuberculosis with biochemical analyses and identified ADP-β-D-manno-heptose (ADP-Hep), which mediates type III secretion system-dependent NF-κB activation and cytokine expression. ADP-Hep, but not other heptose metabolites, could enter host cytosol to activate NF-κB. A CRISPR-Cas9 screen showed that activation of NF-κB by ADP-Hep involves an ALPK1 (alpha-kinase 1)-TIFA (TRAF-interacting protein with forkhead-associated domain) axis. ADP-Hep directly binds the N-terminal domain of ALPK1, stimulating its kinase domain to phosphorylate and activate TIFA. The crystal structure of the N-terminal domain of ALPK1 and ADP-Hep in complex revealed the atomic mechanism of this ligand-receptor recognition process. HBP was transformed by host adenylyltransferases into ADP-heptose 7-P, which could activate ALPK1 to a lesser extent than ADP-Hep. ADP-Hep (but not HBP) alone or during bacterial infection induced Alpk1-dependent inflammation in mice. Our findings identify ALPK1 and ADP-Hep as a pattern recognition receptor and an effective immunomodulator, respectively.

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