EXOSC5
Function
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 (PubMed:11782436, PubMed:21269460). In vitro, EXOSC5 does not bind or digest single-stranded RNA and binds to double-stranded DNA without detectable DNase activity (PubMed:20660080).
Involvement in disease
Cerebellar ataxia, brain abnormalities, and cardiac conduction defects
CABAC
An autosomal recessive disorder characterized by global developmental delay, impaired intellectual development and speech delay that are observed in most patients. Disease manifestations are variable and include infantile-onset hypotonia, poor motor development, poor feeding and overall growth, and ataxic gait due to cerebellar ataxia. Additional variable features are dysarthria, nystagmus, variable ocular anomalies, spasticity, hyperreflexia, and non-specific dysmorphic features. Brain imaging shows cerebellar hypoplasia, often with brainstem hypoplasia, enlarged ventricles, delayed myelination, and thin corpus callosum. A significant number of patients develop cardiac conduction defects in childhood or adolescence.
None
The disease is caused by variants affecting the gene represented in this entry.
Sequence Similarities
Belongs to the RNase PH family.
Tissue Specificity
Highly expressed in a variety of hematopoietic and epithelial tumor cell lines, but not in normal hematopoietic tissues or other normal tissue, with the exception of testis.
Cellular localization
- Nucleus
- Nucleolus
- Cytoplasm
- Nucleus
Alternative names
CML28, RRP46, EXOSC5, Exosome complex component RRP46, Chronic myelogenous leukemia tumor antigen 28, Exosome component 5, Ribosomal RNA-processing protein 46, p12B