DNAAF5 biological notes

DNAAF5/HEATR2 supports cytoplasmic preassembly of the axonemal dynein machinery rather than supplying the motor power stroke. Human airway deficiency, fly knockdown and algal silencing converge on dynein-arm defects and impaired motility. Inner-arm effects depend on subtype and context: retained DNAH7 in the earlier human study and variable algal effects must not be described as loss of every inner-arm species. Human endogenous HEATR2 associates with DNAI2 in mature bronchial cultures, supporting the specific intermediate-chain-binding assertion without establishing purified binary affinity PMID:23040496(https://doi.org/10.1016/j.ajhg.2012.08.022), PMID:25232951(https://doi.org/10.1371/journal.pgen.1004577).

Developmental state matters for the assembly-factor interactions. The 2014 DNAI2 co-immunoprecipitation used terminally differentiated day-40 human airway cultures. Its negative HSP70/HSP90 and other-factor tests do not establish universal absence of those associations. The 2018 study independently examines early assembly-factor expression and HEATR2-EGFP complexes in human airway cultures, with controlled fluorescent-protein FRET in HEK293T cells. HEATR2–SPAG1 and HEATR2 self-proximity were positive; the interpretation explicitly states “HEATR2 interacts indirectly with DNAAF2”. SPAG1-mediated association and a higher-order HEATR2 scaffold model are distinguished from a measured scaffold architecture or autonomous chaperone activity. Main Results/Figure 3 and main Methods were read; detailed supplementary construct-generation methods were not recovered PMID:29358401(https://pmc.ncbi.nlm.nih.gov/articles/PMC5819421/#sec2).

The early human studies establish a diffuse or granular cytoplasmic pool and negative ciliary localization in the tested cells. They predate the DynAP definition. Later human assembly-factor/dynein foci and direct Xenopus fluorescent-Heatr2 imaging support the DynAP interpretation. Xenopus Heatr2 knockdown reduces particle numbers and alters Ktu mobility; these are not human live-dynamics measurements. The human staining in the 2018 DynAP supplement uses LRRC6/DNAI1, while the Heatr2 live-imaging constructs are Xenopus. The 2020 follow-up distinguishes dynein subregions within DNAAF/chaperone-marked particles. Neither experiment requires a fixed stoichiometric human complex PMID:29358401(https://doi.org/10.1073/pnas.1715915115), PMID:30561330(https://doi.org/10.7554/eLife.38497), PMID:33263282(https://doi.org/10.7554/eLife.58662).

The current HPA record supports cytosol in U2OS and ASC52telo cells with antibody HPA060196; it also reports other locations in other assay contexts. This review preserves the existing cytosol assertion without claiming an exclusive distribution or independently interpreting image pixels. The three broad cytoplasm annotations are refined to cytosol and DynAP, which retain distinct soluble/particulate scope. The two NOT motile-cilium assertions remain negative observations in their experimental scope HPA DNAAF5 subcellular record.

Official products are Q86Y56-1 (855 residues), Q86Y56-2 (843 residues; alternative final sequence), and Q86Y56-3 (235 residues; canonical residues 621–855). Each sequence was reconstructed from the official alternative-sequence features and matched to the corresponding official FASTA. The 2014 pathogenic splice frameshift is not the natural isoform-2 tail. No accession-resolved comparison establishes equal function or inactivity of the three natural products UniProt Q86Y56, PMID:25232951(https://doi.org/10.1371/journal.pgen.1004577).

The actual family tree places the human protein below PTN000416608, and its 855-residue aligned sequence matches the official sequence exactly. Four literal assertions at that node are present in the saved IBD snapshot; the current sperm-motility assertion is not present in that snapshot. Direct fly HEATR2 experimental records and the original sperm phenotype support its biological scope without treating donor count or human self-grounding as defects. No new annotation is needed to repeat the existing binding, arm-assembly or DynAP coverage; the performed assembly role is supported independently of a motility phenotype alone.

Access and reproducibility

Ordinary gene/publication fetching succeeded in an isolated workspace. Falcon failed authentication (HTTP 403), and its configured perplexity-lite fallback failed for insufficient quota (HTTP 401). Their actual outputs remain preserved; no provider report was fabricated. The 2012 publication cache remains abstract-only, supplemented by explicitly limited indexed original text/figure context. The 2014, 2018 DynAP and 2020 DynAP caches contain full text. The early-complex 2018 cache remains abstract-only despite independent access to selected original text. No publication cache was edited. Public evidence locators and source distinctions are in DNAAF5-source-evidence.yaml. Final ordinary validation, status derivation and rendering are performed by the publisher on the qualified canonical runtime.