The phospho-barcode of RIPK1: complementarity or redundancy?

Receptor interacting serine/threonine kinase 1 (RIPK1) is the central mediator of tumor necrosis factor (TNF) signaling. It regulates both pro-survival/pro-inflammatory and cell death pathways. In order to fulfill this complex regulation, RIPK1 is regulated by several post-translational modifications, including ubiquitination, acetylation, and phosphorylation. In our recent work, we show that the unc-51-like autophagy activating kinase 1 (ULK1) phosphorylates RIPK1 at Ser357 and thus blocks TNF-induced cell death.