A NOD2-Encoded Toggle Switch Resolves the Host-Microbe Battle Over Cyclic AMP Control

Pathogens hijack macrophages by triggering pathological cAMP surges that block phagolysosomal killing-a defect mirrored in phagocytes from refractory colitis. We identify a host-encoded, pathogen-specific surge-protector comprised of a three-protein toggle: The innate sensor NOD2 binds and masks an evolutionarily conserved motif in GIV that activates trimeric-GTPase Gαi , enforcing a biphasic surge-to-plunge cAMP-program : early, NOD2•GIV assembly permits a brief, tolerogenic cAMP rise, whereas subsequent GIV•Gαi engagement collapses cAMP to drive phagolysosomal fusion and microbial clearance. Structural, biochemical, and ultrastructural analyses reveal how molecular toggling imposes precise spatial and temporal control. Pharmacogenomic perturbations pinpoint cAMP-PKA hyperactivation as the defining lesion in GIV-deficient macrophages. Functional studies in primary macrophages and human gut organoid co-cultures show that toggling the NOD2•GIV•Gαi-axis is necessary and sufficient to convert tolerant macrophages into microbicidal machines that preserve mucosal barrier integrity. These findings uncover a druggable cAMP-control pathway with therapeutic promise in colitis.

Pathogens hijack macrophages by inducing cAMP surges that help them evade clearance. Anandachar et al. identify a host "toggle switch" in which NOD2 and G proteins compete for GIV, driving a rapid and robust surge-to-plunge transition in cAMP. This temporal switch limits tolerogenic signaling, restores microbial clearance and barrier integrity, and unveils a targetable host pathway in infection and IBD.

Pathogens exploit cAMP surges in macrophages to block phagolysosomal killing of microbesGIV acts as a molecular "toggle" linking NOD2 sensing to Gαi-mediated cAMP controlStructural and mutagenesis studies reveal mutually exclusive binding of NOD2 and Gαi to GIVPharmacogenomic perturbations pinpoint PKA, not EPAC, as the critical downstream effectorOrganoid co-cultures show NOD2-GIV-PKA crosstalk safeguards microbial clearance and gut barrier integrity.