Study In The Interaction Proteins Of PIH1D1

PIH1D1 a scaffold protein belongs to the R2TP complex (Rvb1/Rvb2/Tah1/Pih),which stay conserved in mammalian and other species. The function of the R2TP complex is more specifically related to maturation/assembly of certain protein complexes such as snoRNP biogenesis, PIKKs signal-ling, and RNA polymerasc II. The formation of the human R2TP complex is still unknow. However, Pihl is an unstable protein and is prone to be targeted for degradation in vivo and to aggregation in vitro. However, Pih1 is stabilized by its binding to Hsp90 and Tah1.C-terminus of Pihl was found to bind to the C-terminus of Tah1 and other complex. Recently,The R2TP complex has been considered to play an important role in many biological pathways. Suchas,the R2TP-Hsp90 complex together with Prefoldin-like complex (PFDN2, PFDN6, UXT, RPB5, WDR92/Monad, PDRG1, and URI) have been identified as RNA polymerase II (RNAP II) interacting proteins and have been shown to be involved in RNAP II assembly; the R2TP complex has been found to be involved in phosphatidylinositol-3 kinase-related protein kinasc (PIKK) signal-ling pathways; The reduction in endogenous PIH1D1 by siRNA enhanced apoptosis and caspase-3 activation induced by doxorubicin in U2OS cells.; Human Pih1D1 directly associates with fibrillarin/Nopl, Nop58, and Nop56 to affect the assembly and translocation from the nucleoplasm to the nucleolus.In R2TP complex, Pih1 binds Tah1, Hsp90, and the Rvbs. More recently, the C-terminus of Pihl was found to bind to the C-terminus of Tah1. At the same time,Pih1 is an unstable protein and is prone to be targeted for degradation in vivo and to aggregation in vitro. While present researchs on R2TP complex are focus on RPAP3, known data show rpap3 are mostly distributed in the cytoplasm, at meanwhile PIH1D1 distributed both in the cytoplasm and nucleus.especially the nucleolar localization of PIH1D1 shows it may have some function independents of R2TP complex. So a PIHID1 stable-expressed HEK293T cell line was constructed using a FLAG-HA double-tagged PIHID1 expressing plasmid. After performing the FLAG-HA tandem affinity purification (TAP), the mass spectrometric was carried out to analyze the interaction protein complex of PIH1D.