Interaction between the transcription factor SPBP and the positive cofactor RNF4. An interplay between protein binding zinc fingers.

The activator of stromelysin 1 gene transcription, SPBP, interacts with the RING finger protein RNF4. Both proteins are ubiquitously expressed and localized in the nucleus. RNF4 facilitates accumulation of specific SPBP-DNA complexes in vitro and acts as a positive cofactor in SPBP-mediated transactivation. SPBP harbors an internal zinc finger of the PHD/LAP type. This domain can form intra-chain protein-protein contacts in SPBP resulting in negative modulation of SPBP-RNF4 interaction.