| Claim/Topic | Key details (including module/subcomplex, localization) | Evidence type (review/primary; organism/cell type) | Quantitative/statistical data | Source (first author year, journal) and URL/DOI | Context citation ID |
|---|---|---|---|---|---|
| Identity verification: Ndufb1 corresponds to NDUFB1/MNLL accessory subunit of complex I | UniProt target P0DN34 names mouse Ndufb1 as “NADH dehydrogenase [ubiquinone] 1 beta subcomplex subunit 1,” with aliases Complex I-MNLL/CI-MNLL; structural literature explicitly equates MNLL with NDUFB1 in mitochondrial complex I | Structural primary literature; mitochondrial complex I from yeast with comparison to mouse/mammals | Complex I described as ~1 MDa membrane protein complex with ~30 accessory subunits in mitochondria | Parey 2018, *eLife*. https://doi.org/10.7554/eLife.39213 | (pqac-00000008, pqac-00000007) |
| Core biochemical function of the host complex containing NDUFB1 | NDUFB1 is not the catalytic redox center itself; it is an accessory subunit of respiratory complex I, the enzyme that transfers electrons from NADH to ubiquinone and couples this to proton translocation across the inner mitochondrial membrane | Structural/mechanistic primary literature; mitochondrial complex I | Complex I is ~1 MDa; electron transfer from NADH to ubiquinone drives proton pumping | Parey 2018, *eLife*. https://doi.org/10.7554/eLife.39213 | (pqac-00000008) |
| Localization/topology | NDUFB1 belongs to the membrane arm/distal P-module region of mammalian complex I; ND4 module membership implies localization in the inner mitochondrial membrane as part of a membrane-bound assembly intermediate | Review + primary assembly studies; human patient fibroblasts / mammalian complexome data | ND4 module intermediate detected at ~260 kDa in patient complexome profiling | Alahmad 2020, *EMBO Mol Med*. https://doi.org/10.15252/emmm.202012619 | (pqac-00000013, pqac-00000006) |
| Module assignment | NDUFB1 is a constituent of the ND4 module together with ND4, NDUFB5, NDUFB10, and NDUFB11; this places it in the membrane-arm assembly pathway rather than the catalytic N or Q modules | Primary assembly study + review; human fibroblasts and mammalian complex I assembly framework | ND4-module species observed at ~260 kDa | Alahmad 2020, *EMBO Mol Med*. https://doi.org/10.15252/emmm.202012619; Hock 2020, *Biochem J*. https://doi.org/10.1042/BCJ20190767 | (pqac-00000013, pqac-00000012, pqac-00000011) |
| Order of assembly within ND4 pathway | Review evidence indicates a subcomplex containing NDUFB5, NDUFB6, NDUFB10, and NDUFB11 assembles first, followed by addition of NDUFB1 and mtDNA-encoded ND4, placing NDUFB1 in a later step of ND4-module maturation | Review synthesizing gene-edited/complexome studies; mammalian systems | No NDUFB1-specific numeric effect in excerpt; sequence of assembly reported qualitatively | Hock 2020, *Biochem J*. https://doi.org/10.1042/BCJ20190767 | (pqac-00000012, pqac-00000011) |
| Role in complex I assembly/stability | Reviews integrating knockout work report that NDUFB1 is needed for stabilization of the PP-b/PD-a subassembly; NDUFB1 loss blocks complex I assembly and reduces abundance of assembled enzyme | Review drawing on HEK293T KO studies; mammalian cultured cells | Qualitative: KO “blocks CI assembly” and decreases abundance of assembled complex I | Padavannil 2022, *Front Mol Biosci*. https://doi.org/10.3389/fmolb.2021.798353 | (pqac-00000003, pqac-00000004, pqac-00000005) |
| Consequence of ND4-module disruption | Loss of nuclear subunits of the ND4 module causes turnover of almost all complex I subunits, leaving only a Q/ND1 intermediate intact; by module membership, NDUFB1 is part of this vulnerable assembly unit | Review of mammalian gene-edited models; HEK293T | Qualitative near-complete turnover; surviving intermediate is Q/ND1 | Hock 2020, *Biochem J*. https://doi.org/10.1042/BCJ20190767 | (pqac-00000012, pqac-00000011) |
| NDUFB1 as PD-a/ND4-module marker in assembly studies | In TIMMDC1-deficient cells, BN-PAGE tracking of NDUFB1 alongside NDUFB6/NDUFB11 showed similar assembly patterns and accumulation of a PD-a module-containing subassembly, supporting its use as an ND4/PD-a module marker | Primary assembly study; human cultured cells | No direct NDUFB1-only perturbation quantified in excerpt | Fang 2021, *Cell Reports*. https://doi.org/10.1016/j.celrep.2021.108963 | (pqac-00000014) |
| Contribution to supercomplex/respirasome biology | Perturbation of the PD-a module (the module containing NDUFB1) impaired respirasome assembly, implying that NDUFB1-containing membrane-arm structures support higher-order respiratory organization | Primary assembly/supercomplex study; human cultured cells | Qualitative impairment of respirasome assembly; no NDUFB1-specific percentage provided in excerpt | Fang 2021, *Cell Reports*. https://doi.org/10.1016/j.celrep.2021.108963 | (pqac-00000014) |
| Mouse-specific evidence from complex I-focused studies | Mouse complex I studies are cited in structural and disease-model work; NDUFB1 is part of the mammalian/mouse 45-subunit enzyme, and mouse literature is used as a comparator for conformational and assembly features | Structural/comparative primary literature; mouse heart/mammalian complex I | Mouse complex I referenced as 45-subunit mammalian enzyme; no direct mouse Ndufb1 KO phenotype identified in retrieved evidence | Parey 2018, *eLife*. https://doi.org/10.7554/eLife.39213; Yin 2023, *bioRxiv*. https://doi.org/10.1101/2023.07.17.549284 | (pqac-00000007, pqac-00000008) |
| Limits of current annotation evidence | Retrieved evidence strongly supports identity, localization, and assembly role, but direct mouse Ndufb1-specific loss-of-function phenotype data were not found in the available contexts; most mechanistic evidence comes from mammalian cell lines, patient fibroblasts, and reviews of assembly studies | Evidence-gap statement based on available contexts | No direct mouse Ndufb1 knockout statistics available in retrieved contexts | Synthesized from available sources above | (pqac-00000003, pqac-00000012, pqac-00000013, pqac-00000014) |


*Table: This table summarizes the most relevant evidence supporting annotation of mouse Ndufb1/NDUFB1 (MNLL/CI-MNLL) as a mitochondrial complex I accessory subunit. It emphasizes identity verification, membrane-arm/ND4-module assignment, assembly and stability roles, and the current lack of direct mouse-specific knockout evidence in the retrieved sources.*