May act as a bridging factor mediating the interaction between the R2TP/Prefoldin-like (R2TP/PFDL) complex and U5 small nuclear ribonucleoprotein (U5 snRNP) (By similarity). Required for the interaction of R2TP complex subunit RPAP3 and prefoldin-like subunit URI1 with U5 snRNP proteins EFTUD2 and PRPF8 (By similarity). May play a role in regulating the composition of the U5 snRNP complex (By similarity). Interacts (via HIT-type zinc finger) with RUVBL2 in the presence of ATP or ADP; shows a stronger interaction in the presence of ADP. Low expression in most tissues; highly expressed in testis; particularly in seminiferous tubules.