DNALI1

DNALI1 is an axonemal inner dynein arm light intermediate chain that functions in the assembly of motile sperm flagella and, in elongating spermatids, in manchette-based cargo transport during spermiogenesis (PMID:36792588, PMID:37083624). As a structural subunit of a partial inner dynein arm subspecies, it is recruited to flagellar IDAs together with the heavy chains DNAH1, DNAH7, DNAH3, and DNAH12, and its loss disrupts assembly and transport of the fibrous sheath proteins AKAP3 and AKAP4 (PMID:36792588, PMID:41731497). Recruitment of DNALI1 to inner dynein arms depends on partner heavy chains: absence of DNAH3 or DNAH12 abolishes DNALI1 localization to flagellar IDAs, with DNAH12 acting in a flagellum-specific manner without affecting ciliary organization [PMID:41731497, PMID:bio_10.1101_2024.06.20.599934]. Beyond the axoneme, DNALI1 stabilizes PACRG and is required for localization of the MEIG1/PACRG complex within the spermatid manchette, where it supports transport of cargo such as SPAG16L without altering total cellular levels of these proteins (PMID:37083624). Loss-of-function in mice causes impaired sperm motility, abnormal fibrous-sheath ultrastructure, and male infertility, and biallelic patient mutations link DNALI1 to human male infertility (PMID:36792588, PMID:37993789). In a non-ciliary pathological context, DNALI1 overexpression inhibits autophagosome–lysosome fusion and reduces autophagic flux during traumatic brain injury, while its silencing enhances autophagic flux and alleviates neurodegeneration (PMID:38348540).

1. 2006 Medium

   Established the first molecular partner of DNALI1, placing it in physical association with cytoplasmic dynein heavy chain 1 in flagella and cilia, before any functional role was known.

   Evidence Yeast two-hybrid screen of murine testicular cDNA with reciprocal co-IP and immunofluorescence co-localization

   PMID:16496424

   Open questions at the time

   • Did not define a functional consequence of the interaction
   • No knockout or phenotypic data
   • Interaction mapped only to the heavy chain C-terminus
2. 2023 High

   Defined DNALI1 as a light intermediate chain of a partial inner dynein arm subspecies and showed it is required for fibrous sheath protein assembly, linking it to human male infertility.

   Evidence Biallelic patient mutation analysis, Dnali1-/- mouse, immunoprecipitation, immunofluorescence, and TEM

   PMID:36792588

   Open questions at the time

   • Mechanism by which DNALI1 directs AKAP3/AKAP4 assembly unspecified
   • Stoichiometry within the IDA subspecies undefined
   • DNAH10 excluded but full heavy-chain composition incomplete
3. 2023 High

   Identified a manchette-based role distinct from the axoneme, showing DNALI1 stabilizes PACRG and positions the MEIG1/PACRG complex for cargo transport during spermatid elongation.

   Evidence Reciprocal co-IP, pull-down, conditional Dnali1 knockout mouse, and spermatid immunofluorescence

   PMID:37083624

   Open questions at the time

   • Direct vs indirect nature of the DNALI1-PACRG interaction not fully resolved
   • Transport mechanism of SPAG16L cargo not mechanistically dissected
   • Whether manchette and axonemal roles use the same DNALI1 pool unknown
4. 2023 Medium

   Demonstrated that DNALI1 is required for normal flagellar ultrastructure, with loss causing fibrous-sheath disorganization and motility failure rescuable by ICSI.

   Evidence Nonsense-mutation knockin mouse, sperm motility analysis, TEM, and ICSI rescue

   PMID:37993789

   Open questions at the time

   • Causal link between molecular defect and asymmetric column distribution not resolved
   • Single lab
   • No structural detail on the IDA defect
5. 2024 Medium

   Revealed a context-dependent non-ciliary function in which DNALI1 modulates autophagy by inhibiting autophagosome-lysosome fusion under pathological stress.

   Evidence Overexpression and siRNA knockdown in vitro and in a CTE model with autophagic flux and cell death assays

   PMID:38348540

   Open questions at the time

   • Molecular target controlling fusion not identified
   • No effect under normal conditions leaves physiological relevance unclear
   • Mechanistic link to its axonemal dynein role unexplored
6. 2024 Medium

   Showed that DNAH12 recruits DNALI1 (and DNAH1) to inner dynein arms in a flagellum-specific manner, distinguishing flagellar from ciliary assembly requirements.

   Evidence Co-IP, Dnah12-/- and mutant mouse models, immunofluorescence, TEM, and patient whole-exome sequencing (preprint)

   PMID:bio_10.1101_2024.06.20.599934

   Open questions at the time

   • Preprint, not peer-reviewed
   • Basis of flagellum-specific (vs ciliary) requirement unexplained
   • Direct binding interface undefined
7. 2026 Medium

   Identified DNAH3 as an additional heavy-chain partner whose loss disrupts DNALI1 localization, reinforcing that DNALI1 depends on multiple IDA heavy chains for proper assembly.

   Evidence Co-IP with mass spectrometry, comparative proteomics, Dnah3 knockout mouse, immunofluorescence, and TEM

   PMID:41731497

   Open questions at the time

   • Whether DNAH3 and DNAH12 act in the same or distinct IDA subspecies unclear
   • Direct binding vs co-assembly dependence not separated
   • Single lab

• How DNALI1's axonemal/manchette transport functions mechanistically relate to its pathological autophagy-modulating activity, and what molecular determinant governs each, remains unresolved.
• No shared molecular mechanism identified
• No structural model of DNALI1 within any complex
• Autophagy target of DNALI1 unidentified