NEDD4 binding protein 1 (N4BP1)

NEDD4 binding protein 1 (N4BP1) is a cellular protein characterized by RNA binding, ubiquitin binding, and RNase activity. It acts as a negative regulator of proinflammatory cytokine production by dampening innate immune signals, particularly by modulating Toll-like receptor pathways[4][6][8]. N4BP1 restricts viral replication (such as HIV-1) by binding and degrading specific viral RNAs. It interacts with and is mono- or poly-ubiquitinated by the neuronal precursor cell expressed developmentally down-regulated protein 4-1 (NEDD4-1, a HECT-domain E3 ubiquitin ligase)[5][8]. N4BP1 also inhibits the related E3 ubiquitin ligase ITCH by competing for substrate binding[4][5]. This protein acts as a checkpoint to limit excessive inflammation, and its cleavage by caspase 8 in response to strong pathogens releases its suppression, allowing robust cytokine production[4][6]. N4BP1 is not currently established as a direct therapeutic target, biomarker, or the subject of clinically relevant drug development.

Other names

N4BP1NEDD4-binding partner 1

None known for direct drug targeting. Indirectly, inhibition or activation of this protein could theoretically suppress or potentiate cytokine production, but this remains a research concept and not a drug mechanism.