Unconventional prefoldin RPB5 interactor is a protein that in humans is encoded by the C19orf2 gene.

The protein encoded by this gene binds to RNA polymerase II subunit 5 (RPB5) and negatively modulates transcription through its binding to RPB5. The encoded protein seems to have inhibitory effects on various types of activated transcription, but it requires the RPB5-binding region. This protein acts as a corepressor. It is suggested that it may require signaling processes for its function or that it negatively modulates genes in the chromatin structure. Two alternatively spliced transcript variants encoding different isoforms have been described for this gene. [provided by RefSeq].
Function: Seems to be a scaffolding protein able to assemble a prefoldin-like complex that contains PFDs and proteins with roles in transcription and ubiquitination.