Dissection of kinase-dependent and independent functions of RIPK3 in inflammatory disease

RIPK3 is a key regulator of necroptosis and inflammation, yet the distinct contributions of its kinase-dependent and -independent functions remain poorly understood. Here, we report the generation and characterization of RIPK3 D143N mutant mice, a novel model that selectively ablates kinase activity without inducing apoptosis or altering protein expression. Unlike previously described RIPK3 mutants (D161N/K51A), the D143N variant fully rescues Casp8-deficient embryonic lethality while effectively blocking necroptosis induced by multiple stimuli. In TNF-a-induced SIRS, we demonstrated that RIPK3's non-kinase activity exacerbates inflammation and tissue damage through JAK-STAT activation. Similarly, the kinase-independent RIPK3 activity promoted influenza-induced pathogenesis. Our findings establish the D143N mutant as a unique tool for dissecting non-catalytic functions of RIPK3, and provide critical insights for targeting RIPK3 for disease treatment.