DDX19B is an ATP-dependent RNA helicase that functions as a remodeler of ribonucleoprotein particles during mRNA export from the nucleus. Rather than unwinding RNA duplexes, DDX19B dissociates nuclear RNA-binding proteins and facilitates their replacement by cytoplasmic mRNA-binding proteins as mRNPs transit the nuclear pore complex. This remodeling activity is spatially coordinated through interactions with Gle1 and Nup42, and is regulated by SUMOylation at lysine 26, which enhances its binding to Gle1 1. DDX19B additionally regulates perinuclear translation by tethering the translation initiation factor CTIF, restricting cap-binding complex-dependent translation to the perinuclear region 2. DDX19B has emerged as a therapeutic target in leukemia. Recent evidence indicates that DDX19B modulates sensitivity to selinexor, an XPO1 inhibitor, by regulating MCL1 mRNA nuclear export; depletion of both DDX19A and DDX19B sensitizes B-ALL and T-ALL lines to selinexor-induced apoptosis, suggesting DDX19B expression levels may serve as a biomarker for selinexor treatment response 3. Additionally, DDX19B participates in genome stability through its role in DNA damage response pathways 4. Clinical associations include male infertility phenotypes (spermatogenic failure, azoospermia) and cardiovascular disease, though the mechanistic basis of these associations remains unclear.