May act as a bridging factor mediating the interaction between the R2TP/Prefoldin-like (R2TP/PFDL) complex and U5 small nuclear ribonucleoprotein (U5 snRNP) (PubMed:28561026). Required for the interaction of R2TP complex subunit RPAP3 and prefoldin-like subunit URI1 with U5 snRNP proteins EFTUD2 and PRPF8 (PubMed:28561026). May play a role in regulating the composition of the U5 snRNP complex (PubMed:28561026).