NRBP
NRBP1 and NRBP2 are pseudokinases that retain the protein kinase fold while lacking catalytic residues, and they were first identified through interaction screens with nuclear receptors. The two form homo- and heterodimers and function as substrate receptors for Cullin 3-based ubiquitin ligase complexes, recruiting partners for degradation. Each protein also carries a ubiquitin-associated (UBA) domain, consistent with a role in reading ubiquitin signals. NRBP1 has been reported to restrain proliferation and to modulate growth factor signaling, and its expression changes in several tumors. As a result, the NRBP pair is studied mainly as ubiquitin-pathway adaptors, and recombinant proteins support structural and E3-ligase reconstitution experiments.
