The function of DDX31 (DEAD-box helicase 31, ENSG00000125485) is as follows. May have DNA helicase activity and RNA helicase activity. Probably have ssDNA and RNA dependent ATPase activity (By similarity). Plays a role in ribosome biogenesis and TP53/p53 regulation through its interaction with NPM1 (PubMed:23019224). {ECO:0000250|UniProtKB:Q8IBN8, ECO:0000269|PubMed:23019224}.