double-stranded RNA-specific adenosine deaminase (DRADA, DSRAD, 136 kDa double-stranded RNA binding protein, p136, K88DSRBP, denosine deaminase RNA-specific 1 ADAR, ADAR1)
Jump to navigation
Jump to search
Function
- converts multiple adenosines to inosines & creates I/U mismatched base pairs in double-helical RNA substrates without apparent sequence specificity
- modifies adenosines more frequently in AU-rich regions, probably due to the relative ease of melting A/U base pairs as compared to G/C pairs
- functions to modify viral RNA genomes & may be responsible for hypermutation of certain negative-stranded viruses
- edits mRNAs for glutamate receptor (GLUR) subunits by site- selective adenosine deamination; produces low-level editing at the GLUR-B Q/R site, but edits efficiently at the R/G site & HOTSPOT1
- binds to short interfering RNAs (siRNA) without editing them & suppresses siRNA-mediated RNA interference
- binds to ILF3/NF90 & up-regulates ILF3-mediated gene expression
- sumoylation reduces RNA-editing activity
- isoform 1 interacts with ILF2/NF45 & ILF3/NF90
Structure
- homodimer
- contains 1 A to I editase domain
- contains 2 DRADA repeats
- contains 3 DRBM (double-stranded RNA-binding) domains
Compartment
- cytoplasm, nucleus, nucleolu
- isoform 1 is found predominantly in cytoplasm but appears to shuttle between the cytoplasm & nucleus
- isoform 5 is found exclusively in the nucleolus
Alternative splicing
Expression
- ubiquitously expressed
- highest levels found in brain & lung
- isoform 1 is induced by interferon alpha
- isoform 5 is constitutively expressed
Pathology
- defects in ADAR are a cause of dyschromatosis symmetrical hereditaria