Syk kinase-coupled C-type lectin receptors engage protein kinase C-δ to elicit Card9 adaptor-mediated innate immunity.

C-type lectin receptors (CLRs) that couple with the kinase Syk are major pattern recognition receptors for the activation of innate immunity and host defense. CLRs recognize fungi and other forms of microbial or sterile danger, and they induce inflammatory responses through the adaptor protein Card9. The mechanisms relaying CLR proximal signals to the core Card9 module are unknown.

Multiple ITAM-coupled NK-cell receptors engage the Bcl10/Malt1 complex via Carma1 for NF-kappaB and MAPK activation to selectively control cytokine production.

Natural killer (NK) cells are innate immune cells that mediate resistance against viruses and tumors. They express multiple activating receptors that couple to immunoreceptor tyrosine-based activation motif (ITAM)-containing signaling chains for downstream cell activation. Ligation of activating NK-cell receptors induces NK-cell cytotoxicity and cytokine release.