ATP-dependent RNA helicase involved in mRNA export from the nucleus (PubMed:10428971). Rather than unwinding RNA duplexes, DDX19B functions as a remodeler of ribonucleoprotein particles, whereby proteins bound to nuclear mRNA are dissociated and replaced by cytoplasmic mRNA binding proteins (PubMed:10428971). . This is the function of DDX19B (DEAD-box helicase 19B, Ensembl gene identifier ENSG00000157349).