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Mol Cell. 2012 Jun 29;46(6):735-45. doi: 10.1016/j.molcel.2012.05.029. Epub 2012 Jun 14.

Cyclic di-GMP sensing via the innate immune signaling protein STING.

Author information

1
Department of Biochemistry, Weill Cornell Medical College, New York, NY 10065, USA. qiy2001@med.cornell.edu

Abstract

Detection of foreign materials is the first step of successful immune responses. Stimulator of interferon genes (STING) was shown to directly bind cyclic diguanylate monophosphate (c-di-GMP), a bacterial second messenger, and to elicit strong interferon responses. Here we elucidate the structural features of the cytosolic c-di-GMP binding domain (CBD) of STING and its complex with c-di-GMP. The CBD exhibits an α + β fold and is a dimer in the crystal and in solution. Surprisingly, one c-di-GMP molecule binds to the central crevice of a STING dimer, using a series of stacking and hydrogen bonding interactions. We show that STING is autoinhibited by an intramolecular interaction between the CBD and the C-terminal tail (CTT) and that c-di-GMP releases STING from this autoinhibition by displacing the CTT. The structures provide a remarkable example of pathogen-host interactions in which a unique microbial molecule directly engages the innate immune system.

PMID:
22705373
PMCID:
PMC3697849
DOI:
10.1016/j.molcel.2012.05.029
[Indexed for MEDLINE]
Free PMC Article

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