RIPK1 (RIP, Receptor-interacting serine-threonine kinase 1) belongs to receptor-interacting kinase family transducing TNFR-downstream signals and governing NF-κB-driven inflammation, apoptosis and necroptosis. Equipped with kinase and death domains, RIPK1 is recruited to TNF-R1 complex upon TNF-α stimulation. Ubiquitinated RIPK1 assembles Complex-I to trigger NF-κB activation supporting inflammation and cell survival. Upon de-ubiquitination it translocates to form Complex-II initiating caspase-dependent apoptosis. When caspase-8 is suppressed, RIPK1 interacts with RIPK3 to drive necroptosis. RIPK1 contributes to inflammatory disorders and tumor progression.