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

Miki Yoshida, Makio Saeki, Hiroshi Egusa, Yasuyuki Irie, Yuya Kamano, Shinya Uraguchi, Maki Sotozono, Hitoshi Niwa, Yoshinori Kamisaki

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


We previously characterized RNA polymerase II-associated protein 3 (RPAP3) as a cell death enhancer. Here we report the identification and characterization of splicing isoform of RPAP3, isoform 1 and 2. We investigated the interaction between RPAP3 and PIH1 domain containing protein 1 (PIH1D1), and found that RPAP3 isoform 1, but not isoform 2, interacted with PIH1D1. Furthermore, knockdown of RPAP3 isoform 1 by small interfering RNA down-regulated PIH1D1 protein level without affecting PIH1D1 mRNA. RPAP3 isoform 2 potentiated doxorubicin-induced cell death in human breast cancer T-47 cells although isoform 1 showed no effect. These results suggest that R2TP complex is composed of RPAP3 isoform 1 for its stabilization, and that RPAP3 isoform 2 may have a dominant negative effect on the survival potency of R2TP complex.

Original languageEnglish
Pages (from-to)320-324
Number of pages5
JournalBiochemical and biophysical research communications
Issue number1
Publication statusPublished - 2013 Jan 4
Externally publishedYes


  • Monad
  • PIH1D1
  • Pontin
  • R2TP
  • RPAP3
  • Reptin
  • WDR92

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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