RNA polymerase II subunit 5-mediating protein homolog
URI (also called RNA polymerase II fifth subunit regulatory protein or RMP) is an alpha subunit of prefoldin-like complex (PFDL). PFDL is involved in the cytoplasmic assembly of RNA polymerase II and can interact with other chaperone complexes, like R2TP to form the PAQosome. In the cytoplasm, URI acts as a chaperone protein; in the nucleus, URI acts as a transcription regulator and can interact with RPB5 (a subunit of eukaryotic RNA polymerases) and RNA polymerase II (pol II). Prefoldin is a hexameric molecular chaperone complex, found in both eukaryotes and archaea, that binds and stabilizes newly synthesized polypeptides allowing them to fold correctly. The complex contains two alpha and four beta subunits, the two subunits being evolutionarily related.