PLX079582

GSE83736: Vav proteins are key regulators of Card9 signaling for innate antifungal immunity

• Organsim mouse
• Type RNASEQ
• Target gene
• Project ARCHS4

Fungal infections are major causes of morbidity and mortality, especially in immunocompromised individuals. The innate immune system senses fungal pathogens through a family of Syk-coupled C-type lectin receptors (CLRs), which signal through the conserved immune adapter Card9. Although Card9 complexes are essential for antifungal defense in humans and mice, the mechanisms that couple CLR-proximal events to Card9 control are not well defined. Here, using a proteomic approach, we identified Vav proteins as key activators of the Card9 pathway. Vav1, Vav2 and Vav3 cooperate downstream of Dectin-1, Dectin-2 and Mincle to selectively engage Card9 for NF-B control and proinflammatory gene transcription but are not involved in MAPK activation. Although Vav family members show functional redundancy, Vav1/2/3 triple-deficient cells are severely impaired for NF-B and cytokine responses upon stimulation with CLR agonists or hyphae, and Vav1/2/3-/- mice phenocopy Card9-/- animals with extreme susceptibility to fungi and rapid mortality upon Candida albicans infection. In this context, Vav3 is the single most important Vav in mice, and a polymorphism in human VAV3 is associated with susceptibility to candidemia in patients. Our results reveal a molecular mechanism for CLR-mediated Card9 regulation that controls innate immunity to fungal infections. SOURCE: Assa Yeroslaviz (yeroslaviz@biochem.mpg.de) - Max-Planck-Institute for biochemistry