Our study have shown that PPDPF promoted NF-κB activation through TRIM21-mediated K63-linked ubiquitination of RIPK1 in hepatocytes. Upon TNF-α stimulation, PPDPF enhances TRIM21/RIPK1 interaction and increases TRIM21-mediated K63-linked ubiquitination of RIPK1, which promotes NF-κB activation.To map the ubiquitination site of RIPK1 regulated by PPDPF, we performed MS analysis using control and RIPK1-overexpressing HEK293T cells with or without PPDPF overexpression