TNIP1 inhibits NF-κB activation and TNF-induced NF-κB-dependent gene expression. It does so by regulating TAX1BP1- and A20/TNFAIP3-mediated deubiquitination of IKBKG, and it is proposed to link A20/TNFAIP3 to ubiquitinated IKBKG. The protein is also involved in the EGF-induced ERK1/ERK2 signalling pathway, where it blocks nuclear translocation of MAPK3/MAPK1 and MAPK1-dependent transcription, and it increases cell surface CD4 antigen expression.

In immune cells, TNIP1 contributes to the anti-inflammatory response of macrophages and positively regulates TLR-induced activation of CEBPB. Its role in preventing autoimmunity implicates binding to polyubiquitin. TNIP1 is also involved in leukocyte integrin activation during inflammation, through association with SELPLG and dependent on phosphorylation by SRC-family kinases. The protein localises to the cytoplasm and nucleus.

TNIP1 also features in host-pathogen biology. It interacts with the HIV-1 matrix protein and is packaged into virions, and overexpression can inhibit viral replication. It may regulate matrix nuclear localisation, including nuclear import of the preintegration complex and export of GAG polyprotein and viral genomic RNA during virion production. During Shigella flexneri infection, TNIP1 promotes association of IKBKG with the bacterial E3 ubiquitin-protein ligase ipah9.8, leading to proteasome-dependent degradation of IKBKG and perturbed NF-κB activation.

The TNIP1 gene encodes an A20-binding protein, and multiple transcript variants encoding different isoforms have been described. Mutations in the gene have been associated with psoriatic arthritis, rheumatoid arthritis and systemic lupus erythematosus. The mouse ortholog is Tnip1.