RPAP3 splicing variant isoform 1 interacts with PIH1D1 to compose R2TP complex for cell survival

► RPAP3 isoform 1, but not isoform 2, interacted with PIH1D1. ► RPAP3 isoform 2 potentiated doxorubicin-induced cell death. ► RPAP3 isoform 2 may have a dominant negative effect on R2TP complex.