PIH1 domain-containing protein 1 (PIH1D1)

PIH1 domain-containing protein 1 (PIH1D1) is a molecular scaffold and substrate recognition subunit of the R2TP complex, an HSP90 co-chaperone system required for the assembly and stabilization of multiple large macromolecular machines, such as small nucleolar ribonucleoproteins (snoRNPs), RNA polymerase II, and the mTORC1 and SMG1 kinase complexes[2][3][4]. PIH1D1 contains a phosphopeptide-binding PIH-N domain that specifically recognizes phosphorylated motifs, recruiting phosphorylated client proteins (e.g., TEL2, ECD) in a highly sequence-specific and phosphorylation-dependent manner[2][3]. Through this substrate recognition, PIH1D1 orchestrates proper assembly and stability of multisubunit factors involved in transcription, ribosome biogenesis, and cell signaling, with key localizations in the cytoplasm and nucleolus[1][4]. Defects or mutations can lead to diseases involving ribonucleoprotein assembly or ciliary function, such as primary ciliary dyskinesia[4]. There are currently no direct inhibitors, drugs, or biomarkers in clinical use for PIH1D1.

Other names

NOP17FLJ20643Pih1MOT48DNAAF14Nucleolar protein 17 homologDynein axonemal assembly factor 14