ATP-dependent RNA helicase DDX3X

DDX3X (ATP-dependent RNA helicase DDX3X) is a multifunctional RNA helicase that unwinds partially double-stranded nucleic acids and binds RNA G-quadruplex structures (UniProt: O00571). Beyond its catalytic activities, it regulates transcription, translation initiation of complex mRNAs with structured 5'-UTRs, and ribosome assembly. The protein also functions in innate immunity as a viral RNA sensor, promoting type I interferon production through IRF3/IRF7 and NF-κB pathways, and plays roles in stress granule assembly and inflammasome regulation.

DDX3X is widely expressed and involved in multiple cellular processes including cell cycle regulation, apoptosis, and Wnt signaling. Mutations cause X-linked intellectual developmental disorder with syndromic features (MRXSSB, MIM 300958), indicating its importance in neurodevelopment (UniProt: O00571). The protein also facilitates replication of several viruses including HIV-1, HCV, and Zika virus.

In Alzheimer's disease, DDX3X is upregulated in post-mortem AD brain tissue compared to age-matched controls, with a mean log2 fold-change of +0.25 (Chaparral AD proteomics). This upregulation was detected in one subcellular fraction from a TMT-labeled proteomics study, suggesting potential involvement in AD pathobiology, though the functional significance remains to be determined.