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

Biochemical and biophysical research communications 2013 Jan 04

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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. Copyright © 2012 Elsevier Inc. All rights reserved.

Citation

Miki Yoshida, Makio Saeki, Hiroshi Egusa, Yasuyuki Irie, Yuya Kamano, Shinya Uraguchi, Maki Sotozono, Hitoshi Niwa, Yoshinori Kamisaki. RPAP3 splicing variant isoform 1 interacts with PIH1D1 to compose R2TP complex for cell survival. Biochemical and biophysical research communications. 2013 Jan 04;430(1):320-4