Exosome complex component RRP4 (Exosome component 2) (Ribosomal RNA-processing protein 4)
1_MAMEM 6_ RLPVA 11_ RKPLS 16_ ERLGR 21_ DTKKH 26_ LVVPG 31_ DTITT 36_ DTGFM 41_ RGHGT 46_ YMGEE 51_ KLIAS 56_ VAGSV 61_ ERVNK 66_ LICVK 71_ ALKTR 76_ YIGEV 81_ GDIVV 86_ GRITE 91_ VQQKR 96_ WKVET 101_ NSRLD 106_ SVLLL 111_ SSMNL 116_ PGGEL 121_ RRRSA 126_ EDELA 131_ MRGFL 136_ QEGDL 141_ ISAEV 146_ QAVFS 151_ DGAVS 156_ LHTRS 161_ LKYGK 166_ LGQGV 171_ LVQVS 176_ PSLVK 181_ RQKTH 186_ FHDLP 191_ CGASV 196_ ILGNN 201_ GFIWI 206_ YPTPE 211_ HKEEE 216_ AGGFI 221_ ANLEP 226_ VSLAD 231_ REVIS 236_ RLRNC 241_ IISLV 246_ TQRMM 251_ LYDTS 256_ ILYCY 261_ EASLP 266_ HQIKD 271_ ILKPE 276_ IMEEI 281_ VMETR 286_QRLLE
1: Non-catalytic component of the RNA exosome complex which has 3'->5' exoribonuclease activity and participates in a multitude of cellular RNA processing and degradation events. In the nucleus, the RNA exosome complex is involved in proper maturation of stable RNA species such as rRNA, snRNA and snoRNA, in the elimination of RNA processing by-products and non-coding 'pervasive' transcripts, such as antisense RNA species and promoter-upstream transcripts (PROMPTs), and of mRNAs with processing defects, thereby limiting or excluding their export to the cytoplasm. The RNA exosome may be involved in Ig class switch recombination (CSR) and/or Ig variable region somatic hypermutation (SHM) by targeting AICDA deamination activity to transcribed dsDNA substrates. In the cytoplasm, the RNA exosome complex is involved in general mRNA turnover and specifically degrades inherently unstable mRNAs containing AU-rich elements (AREs) within their 3' untranslated regions, and in RNA surveillance pathways, preventing translation of aberrant mRNAs. It seems to be involved in degradation of histone mRNA. The catalytic inactive RNA exosome core complex of 9 subunits (Exo-9) is proposed to play a pivotal role in the binding and presentation of RNA for ribonucleolysis, and to serve as a scaffold for the association with catalytic subunits and accessory proteins or complexes. EXOSC2 as peripheral part of the Exo-9 complex stabilizes the hexameric ring of RNase PH-domain subunits through contacts with EXOSC4 and EXOSC7