"The literature summarized here is specifically for **Dbp5** (alias **Rat8**) from *Saccharomyces cerevisiae* (S288c), an essential **DEAD-box ATP-dependent RNA helicase/RNA-dependent ATPase** at the nuclear pore complex (NPC), orthologous to metazoan **DDX19**."

"Dbp5 is a DEAD-box RNA helicase-family protein whose core activity is **RNA-dependent ATP hydrolysis** coupled to **nucleotide-state–dependent conformational cycling**, enabling binding and remodeling of RNA–protein complexes (RNPs) rather than long-range processive duplex unwinding. In the export context, this remodeling function is often described as an **RNPase** activity acting on messenger RNPs at the NPC"

"The mechanistic focus is on Dbp5-driven removal of export-associated factors such as **Mex67–Mtr2** (major mRNA export receptor) and **Nab2** (poly(A) RNA-binding/export factor), thereby enforcing directionality and enabling cytoplasmic fate decisions"

"Directionality is established at the **cytoplasmic NPC face**, where Dbp5 activity promotes dissociation of export factors from the mRNP so that the particle **cannot re-enter the nucleus using the same export-binding interactions**"

"Dbp5 catalyzes **ATP hydrolysis (ATP → ADP + Pi)** in an RNA-dependent manner, with its remodeling function associated with conformational changes across its nucleotide cycle"

"Alcázar-Román et al. (JBC 2010-05-28, https://doi.org/10.1074/jbc.M109.082370) describe Gle1 and IP6 as essential for mRNA export by **activating Dbp5 ATPase** and promoting localized mRNP remodeling and directionality; they also report that the same module is required for **proper translation termination**"

"Noble et al. (Genes & Dev. 2011-05, https://doi.org/10.1101/gad.2040611) conclude that “a primary role for Nup159 in the Dbp5 cycle is to facilitate ADP release,” and show that ADP binding alone is sufficient to drive in vitro remodeling of Nab2-RNPs under their assay conditions"

"Adams et al. (Traffic 2017-10, https://doi.org/10.1111/tra.12526) report that Nup42/hNup42 enhances Gle1 stimulation of the RNA-dependent Dbp5/DDX19B ATPase, and that a **nup42-CTD/gle1-CTD/Dbp5 trimeric complex forms in the presence of IP6**"

"Dbp5 association with NPCs is highly dynamic, with **~0.8 s** average residence time reported by FRAP in yeast"

"Dbp5 binds tRNA in vitro with **Kd ~150 nM** (Phe tRNA) and **~130 nM** (mixed tRNA) (Rajan et al., eLife 2024-01, https://doi.org/10.7554/elife.89835)."

"**tRNA (or dsRNA poly(I:C)) alone does not stimulate Dbp5 ATPase activity**, unlike a typical ssRNA activator (poly(A)). However, **tRNA/dsRNA synergizes with Gle1/InsP6 to fully activate Dbp5**, reaching ~**1.03 ± 0.04 ATP/s** (mixed tRNA with Gle1/InsP6) comparable to ssRNA activation (~**1.11 ± 0.07 ATP/s**)"

"Rajan et al. (eLife 2024-01) provide genetic and biochemical evidence that Dbp5 functions in tRNA export in a pathway parallel to canonical exporters:"

"Querl & Krebber (Biological Chemistry, published online 2023-07-13, https://doi.org/10.1515/hsz-2023-0130) review evidence that Dbp5 functions in **translation termination**, including a mechanistic model where Dbp5 delivers **eRF1** to terminating ribosomes and prevents premature eRF1–eRF3 interactions, thereby reducing readthrough"

"Querl & Krebber (2023) summarize a model in which Dbp5 contributes to no-go decay (NGD) and non-stop decay (NSD) by delivering rescue factors **Dom34/Hbs1** to stalled ribosomes; subsequent hydrolysis steps coordinate rescue and transcript clearance"

"Recent synthesis also places Dbp5 in pre-ribosomal export, with a model distinct from canonical mRNA remodeling:"