EXOSC2 Protein, Human

EXOSC2, a non-catalytic component of the RNA exosome complex, plays a crucial role in 3'->5' exoribonuclease activity, contributing to diverse cellular RNA processing and degradation events. Within the nucleus, the RNA exosome complex facilitates the proper maturation of stable RNA species, including rRNA, snRNA, and snoRNA, while eliminating RNA processing by-products, non-coding transcripts such as antisense RNA species, promoter-upstream transcripts (PROMPTs), and mRNAs with processing defects. This process limits their export to the cytoplasm. The RNA exosome is implicated in Ig class switch recombination (CSR) and/or Ig variable region somatic hypermutation (SHM), directing AICDA deamination activity to transcribed dsDNA substrates. In the cytoplasm, EXOSC2 contributes to general mRNA turnover and selectively degrades inherently unstable mRNAs with AU-rich elements (AREs) within their 3' untranslated regions, preventing the translation of aberrant mRNAs in RNA surveillance pathways. Additionally, it appears to be involved in the degradation of histone mRNA. As a component of the catalytically inactive RNA exosome core (Exo-9), EXOSC2 plays a crucial role in binding and presenting RNA for ribonucleolysis, serving as a scaffold for the association with catalytic subunits and accessory proteins or complexes. EXOSC2, as a peripheral part of the Exo-9 complex, stabilizes the hexameric ring of RNase PH domain-containing subunits, forming contacts with EXOSC4 and EXOSC7. This multifaceted interaction underscores the versatile role of EXOSC2 in RNA-related processes.