DDX23
Function
Involved in pre-mRNA splicing and its phosphorylated form (by SRPK2) is required for spliceosomal B complex formation (PubMed:18425142). Independently of its spliceosome formation function, required for the suppression of incorrect R-loops formed during transcription; R-loops are composed of a DNA:RNA hybrid and the associated non-template single-stranded DNA (PubMed:28076779).
Post-translational modifications
In vitro phosphorylated by CLK1 and U1 snRNP-associated protein kinase (PubMed:9409622). Phosphorylated by SRPK2 and this phosphorylation is required for its association with the tri-snRNP (U4/U6-U5 tri-small nuclear ribonucleoproteins) and subsequent spliceosomal B complex formation (PubMed:18425142). May be phosphorylated by SRPK2 on Ser residues in the SR domain; the phosphorylation is required for the removal of inappropriate R-loops during transcription (PubMed:28076779).
Sequence Similarities
Belongs to the DEAD box helicase family. DDX23/PRP28 subfamily.
Cellular localization
- Nucleus
- Chromosome
- During transcription, accumulates at chromatin loci where unscheduled R-loops form and colocalizes with paused 'Ser-5'-phosphorylated POLR2A/RNA polymerase II and kinase SRPK2.
Alternative names
Probable ATP-dependent RNA helicase DDX23, 100 kDa U5 snRNP-specific protein, DEAD box protein 23, PRP28 homolog, U5-100kD, DDX23