| Biological role/process | Molecular function / mechanistic concept | Key partners/regulators | Cellular localization | Key quantitative data | Evidence type | Key reference with publication date and URL |
|---|---|---|---|---|---|---|
| **Identity / core enzymology** | Essential **DEAD-box ATPase/RNA helicase (RNPase)** that uses nucleotide-dependent conformational cycling to bind RNA and remodel RNA–protein complexes; ATP-bound state has higher RNA affinity than ADP-bound state, and ATP hydrolysis/conversion to ADP is linked to remodeling competence (pqac-00000019, pqac-00000020, pqac-00000023) | ATP, RNA; regulated by **Gle1-InsP6** and **Nup159** (pqac-00000019, pqac-00000023) | Nucleus, cytoplasm, prominent enrichment at **nuclear rim / cytoplasmic face of NPC** (pqac-00000010, pqac-00000005) | Basal ATPase ~**0.04–0.14 s⁻¹**; RNA stimulation ~**6–20-fold**; Dbp5 favors **ADP ~0.4 mM** over **ATP ~4 mM**; AMP-PNP-bound RNA-binding **K\_d ~40 nM**; RNA binding not detectable with ADP in cited assay (pqac-00000019) | Biochemistry, structural inference, review | Querl & Krebber, **2023-07-13**, https://doi.org/10.1515/hsz-2023-0130 ; mechanistic synthesis from Rajan thesis excerpts **2023** (pqac-00000019) |
| **Bulk mRNA export / export directionality** | Dbp5 remodels emerging **mRNPs** at the cytoplasmic NPC face, removing export factors to prevent nuclear re-entry and enforce **one-way export**; remodeling includes displacement/removal of **Mex67-Mtr2** and **Nab2** from exported mRNPs (pqac-00000009, pqac-00000010, pqac-00000017, pqac-00000018) | **Mex67-Mtr2, Nab2, Gle1, InsP6/IP6, Nup42, Nup159** (pqac-00000009, pqac-00000010, pqac-00000021) | **Cytoplasmic fibrils / cytoplasmic side of NPC** (pqac-00000009, pqac-00000010) | Reporter mRNP translocation through NPC reported as **~0.2 s** and **<0.5 s**; Dbp5 residence at NPC **~0.8 s** by FRAP; NPC exports an mRNP every **~2–6 s** (pqac-00000020, pqac-00000017) | Genetics, imaging, biochemistry, review | Hodge et al., **2011-05**, https://doi.org/10.1101/gad.2041611 ; Alcázar-Román et al., **2010-05-28**, https://doi.org/10.1074/jbc.M109.082370 ; Querl & Krebber, **2023-07-13**, https://doi.org/10.1515/hsz-2023-0130 |
| **mRNP remodeling reaction** | In this context, “mRNP remodeling” means **Dbp5-driven displacement/restructuring of mRNP components**, especially release of export adaptors from RNA; in vitro, **ADP-bound/conversion-to-ADP** states are remodeling-competent for **Nab2-RNP** remodeling (pqac-00000023, pqac-00000017) | **Nab2**, RNA, nucleotide state; **Gle1-InsP6** promotes productive cycling (pqac-00000023, pqac-00000019) | Cytoplasmic NPC face (pqac-00000022, pqac-00000024) | Initial Dbp5–ADP on-rate estimate in in vitro remodeling assay: **~7.3% of total ADP bound per min**; distinct Dbp5-ADP CD peak at **~260–270 nm** (pqac-00000023) | In vitro biochemistry, biophysics | Noble et al., **2011-05**, https://doi.org/10.1101/gad.2040611 |
| **Gle1 / InsP6-dependent ATPase activation** | **Gle1 bound to InsP6/IP6** is the principal activator/coactivator of Dbp5 ATPase at the NPC; promotes ATP binding/stimulation and supports full potentiation required for mRNA export and translation termination (pqac-00000009, pqac-00000020, pqac-00000023) | **Gle1, InsP6/IP6**, RNA; coordinated by **Nup42** (pqac-00000009, pqac-00000021) | Cytoplasmic side of NPC, where Gle1 localizes (pqac-00000009) | In structured-RNA assays, Gle1/InsP6 raises Dbp5 ATPase to **1.03 ± 0.04 ATP/s** with mixed tRNA vs **1.11 ± 0.07 ATP/s** with ssRNA; with RNase T1-treated tRNA, activity remains **1.18 ± 0.19 ATP/s** (vs **1.19 ± 0.11 ATP/s** untreated), showing activation depends on structured RNA rather than ssRNA contamination (pqac-00000012) | Biochemistry, genetics | Alcázar-Román et al., **2010-05-28**, https://doi.org/10.1074/jbc.M109.082370 ; Rajan et al., **2024-01**, https://doi.org/10.7554/elife.89835 |
| **Nup159-regulated nucleotide recycling** | **Nup159** tethers Dbp5 at NPC cytoplasmic filaments and primarily facilitates **ADP release / recycling** after remodeling; Nup159 binding is incompatible with RNA binding and helps reset the cycle (pqac-00000014, pqac-00000015, pqac-00000017) | **Nup159**, Dbp5-ADP, Gle1 (interaction weakened by Nup159 in cited synthesis) (pqac-00000014, pqac-00000017) | NPC cytoplasmic filaments (pqac-00000015, pqac-00000010) | Dbp5–Nup159 affinity changes from about **~20 nM** to **~0.6 μM** for Dbp5-ADP and **~1 μM** for Dbp5-ATP in cited in vitro analyses; altered ADP-binding mutant bypasses Nup159 requirement (pqac-00000017, pqac-00000014) | Biochemistry, genetics, FRAP/imaging | Noble et al., **2011-05**, https://doi.org/10.1101/gad.2040611 ; Hodge et al., **2011-05**, https://doi.org/10.1101/gad.2041611 |
| **Nup42 coordination of export remodeling** | **Nup42** does not primarily localize Gle1 but instead enhances **Gle1-mediated stimulation** of RNA-dependent Dbp5 ATPase; supports formation of a **Nup42-CTD/Gle1-CTD/Dbp5** regulatory complex and couples remodeling to Mex67-bound mRNPs (pqac-00000008, pqac-00000021) | **Nup42, Gle1, InsP6/IP6, Dbp5**, Mex67-bound mRNPs (pqac-00000008, pqac-00000021) | Cytoplasmic NPC face (pqac-00000008) | Minimal Gle1-binding peptide in Nup42 is **17 aa (residues 408–424)**; no direct soluble Nup42–Dbp5 interaction detected in cited assay (pqac-00000008, pqac-00000021) | Biochemistry, cell biology | Adams et al., **2017-10**, https://doi.org/10.1111/tra.12526 |
| **tRNA export (recent extension)** | Dbp5 directly binds **tRNA** but tRNA alone does **not** stimulate ATPase; instead, **tRNA + Gle1/InsP6** synergistically activates Dbp5, supporting a parallel Dbp5-dependent tRNA export pathway independent of Los1 (pqac-00000012, pqac-00000013, pqac-00000003) | **tRNA, Gle1, InsP6/IP6**, Los1-independent pathway; not dependent on Los1/Msn5/Mex67 for Dbp5 recruitment to tRNA in vivo (pqac-00000003, pqac-00000013) | Likely exported through NPC with activation at cytoplasmic face (pqac-00000012, pqac-00000013) | tRNA-binding **K\_d ~150 nM** (Phe tRNA) and **~130 nM** (mixed tRNA); tRNA alone does not stimulate ATPase, whereas with Gle1/InsP6 ATPase reaches **1.03 ± 0.04 ATP/s**; **los1Δ gle1-4** causes **~5-fold** increase in pre-tRNA Ile UAU intermediate/precursor ratio after **4 h at 37°C** (pqac-00000012, pqac-00000013) | In vitro biochemistry, EMSA/fluorescence polarization, yeast genetics | Rajan et al., **2024-01**, https://doi.org/10.7554/elife.89835 |
| **Translation termination** | Dbp5 is required for efficient **translation termination**; model from yeast studies/review: Dbp5 delivers **eRF1** to terminating ribosomes and prevents premature eRF1–eRF3 association, thereby reducing readthrough (pqac-00000010, pqac-00000016, pqac-00000000) | **eRF1, eRF3, Gle1, InsP6/IP6** (pqac-00000016, pqac-00000000) | Cytoplasm / translating ribosomes (pqac-00000010, pqac-00000016) | No direct kinetic constant in provided contexts; functional requirement supported by genetics and mechanistic review (pqac-00000010, pqac-00000000) | Genetics, review | Querl & Krebber, **2023-07-13**, https://doi.org/10.1515/hsz-2023-0130 ; Alcázar-Román et al., **2010-05-28**, https://doi.org/10.1074/jbc.M109.082370 |
| **Cytoplasmic mRNA surveillance (NGD/NSD)** | Proposed role in **no-go decay (NGD)** and **non-stop decay (NSD)** by delivering **Dom34/Hbs1** to stalled ribosomes; ATP/GTP hydrolysis steps then enable rescue and subunit splitting (pqac-00000011, pqac-00000016) | **Dom34, Hbs1, Rli1** (pqac-00000011, pqac-00000016) | Cytoplasm, stalled ribosomes (pqac-00000011, pqac-00000016) | No supported numeric kinetic constants in provided contexts (pqac-00000011) | In vivo/in vitro binding studies summarized in review | Querl & Krebber, **2023-07-13**, https://doi.org/10.1515/hsz-2023-0130 |
| **Pre-ribosomal subunit export** | Dbp5 also contributes to **pre-ribosomal subunit export**; review model suggests direct **Mex67** binding captures translocating subunits in cytoplasm, and this role may be less dependent on canonical helicase remodeling than mRNA export (pqac-00000013, pqac-00000016, pqac-00000006) | **Mex67**, pre-ribosomal particles (pqac-00000016, pqac-00000006) | Nuclear export route / cytoplasmic side of NPC (pqac-00000016) | No quantitative values supported in provided contexts (pqac-00000013, pqac-00000016) | Review, prior genetics/cell biology summarized in review | Querl & Krebber, **2023-07-13**, https://doi.org/10.1515/hsz-2023-0130 |


*Table: This table summarizes the experimentally supported functions, mechanisms, partners, localization, and quantitative measurements for Saccharomyces cerevisiae Dbp5/Rat8 (UniProt P20449). It is useful as a compact evidence map linking Dbp5’s ATPase cycle to mRNA export, tRNA export, translation termination, and related RNA quality-control roles.*