Affinage

CCDC39

Coiled-coil domain-containing protein 39 · UniProt Q9UFE4

Length
941 aa
Mass
109.9 kDa
Annotated
2026-06-09
17 papers in source corpus 8 papers cited in narrative 9 extracted findings
Cross-family judge vs UniProt: Affinage preferred faithfulness: 6/6 claims corpus-supported (100%)

Mechanistic narrative

Synthesis pass · prose summary of the discoveries below

CCDC39 is an axonemal protein essential for the assembly and motility of motile cilia and sperm flagella (PMID:21131972). It forms a molecular ruler complex with CCDC40 that establishes and maintains the 96 nm repeat unit along the ciliary axoneme; CCDC40 depends on CCDC39 for its flagellar localization (PMID:39056782, PMID:36873931). This ruler is specifically required for assembly of inner dynein arms and the dynein regulatory complex, and its loss leads to axonemal absence of IDA heavy chains DNAH1, DNAH6, and DNAH7 (including centrin2-containing IDAs) and abnormal assembly of GAS8 and DNALI1, while radial spoke structures remain largely intact (PMID:23255504, PMID:39056782). Loss of CCDC39 produces inner dynein arm absence and microtubular disorganization, abolishing coordinated ciliary beating (PMID:21131972, PMID:23255504). The resulting phenotypes span multiple ciliated tissues: respiratory primary ciliary dyskinesia from defective mucociliary clearance, hydrocephalus from impaired ependymal cilia-driven CSF flow, and male infertility with multiple morphological abnormalities of sperm flagella (PMID:22693285, PMID:29317443, PMID:34674941). Pathogenic CCDC39 alleles establish it, together with CCDC40, as a primary genetic cause of PCD with axonemal disorganization and IDA loss (PMID:23255504).

Mechanistic history

Synthesis pass · year-by-year structured walk · 9 steps
  1. 2010 High

    Established CCDC39 as an axonemal protein whose loss disrupts inner dynein arm and dynein regulatory complex assembly, answering what cellular structure depends on it.

    Evidence Positional cloning in dogs, human loss-of-function mutation identification, immunofluorescence to ciliary axonemes, and ciliary motility analysis

    PMID:21131972

    Open questions at the time
    • Did not define a direct molecular partner of CCDC39
    • Mechanism by which it specifies IDA/DRC assembly not yet established
    • Did not address sperm flagella
  2. 2012 High

    Extended the requirement for CCDC39 from respiratory cilia to sperm flagella, showing the same axonemal defect underlies male infertility.

    Evidence CCDC39 sequencing in patient cohort with quantitative TEM of cilia and sperm flagella

    PMID:22693285

    Open questions at the time
    • Did not identify which specific IDA subtypes are lost
    • No molecular interaction partners defined
  3. 2013 High

    Defined CCDC39 (with CCDC40) as a primary cause of PCD via null alleles and localized the ultrastructural defect specifically to IDAs and microtubular disorganization, sparing radial spokes.

    Evidence Sequencing of CCDC39 and CCDC40 in 54 families with TEM ultrastructure

    PMID:23255504

    Open questions at the time
    • Did not establish the physical CCDC39–CCDC40 interaction directly
    • Molecular ruler function not yet demonstrated
  4. 2018 High

    Demonstrated in a mammalian genetic model that CCDC39 in ependymal and choroid plexus motile cilia drives unidirectional CSF flow, linking its axonemal role to hydrocephalus.

    Evidence Whole-genome sequencing of prh mouse mutant, immunofluorescence, high-speed video microscopy, and TEM

    PMID:29317443

    Open questions at the time
    • Did not resolve cell-autonomous vs systemic contributions to hydrocephalus
    • Adult versus developmental requirement not separated
  5. 2019 Medium

    Placed Ccdc39 in a genetic interaction with L1cam in CSF flow regulation, showing combinatorial control of hydrocephalus severity.

    Evidence CRISPR/Cas9 knockin rat model with MRI, glymphatic flow assessment, and epistasis with L1cam

    PMID:31771992

    Open questions at the time
    • Molecular basis of the Ccdc39–L1cam interaction unknown
    • Single lab
  6. 2021 Medium

    Showed a missense allele behaves as loss-of-function by destabilizing CCDC39 protein and causing MMAF, connecting protein abundance to flagellar morphology.

    Evidence Whole-exome sequencing, TEM, immunofluorescence, and western blot in a single family

    PMID:34674941

    Open questions at the time
    • Single case/family, single lab
    • Did not define why p.Leu328Pro destabilizes the protein
  7. 2023 Medium

    Provided direct evidence of CCDC39–CCDC40 co-dependency in flagella, showing CCDC40 requires CCDC39 for its flagellar localization.

    Evidence Immunofluorescence of sperm flagella from CCDC39-mutant patients with NGS

    PMID:36873931

    Open questions at the time
    • Did not demonstrate a direct biochemical interaction
    • Reciprocal dependency (CCDC39 on CCDC40) not tested here
    • Single lab
  8. 2024 Medium

    Defined the CCDC39/CCDC40 complex as a 96 nm molecular ruler and identified the specific IDA components (DNAH1/6/7, centrin2-IDAs, GAS8, DNALI1) whose assembly depends on it.

    Evidence Immunofluorescence of respiratory ciliary axonemes in 51 individuals with NGS variant identification

    PMID:39056782

    Open questions at the time
    • Single primary method (IF), single lab
    • Direct biochemical reconstitution of ruler periodicity not shown
    • Mechanism of how the ruler templates 96 nm spacing not resolved
  9. 2025 Low

    Isolated the adult-specific requirement for CCDC39 in ependymal cilia, showing its loss causes transient ventricular enlargement and microglial response distinct from developmental defects.

    Evidence Conditional ependymal knockout mouse with MRI volumetry and immunohistochemistry (preprint)

    Open questions at the time
    • Preprint, single lab, limited methodological detail
    • Mechanism linking ciliary loss to microglial density not established
    • Transient nature of phenotype not mechanistically explained

Open questions

Synthesis pass · forward-looking unresolved questions
  • How the CCDC39/CCDC40 ruler physically templates the 96 nm axonemal repeat and selectively recruits specific IDA subtypes remains to be defined at the structural and biochemical level.
  • No structural model of the CCDC39/CCDC40 ruler in the timeline
  • Direct binding of CCDC39 to individual IDA components not demonstrated
  • Mechanism of periodicity measurement unresolved

Mechanism profile

Synthesis pass · controlled-vocabulary classification · explore literature graph →
Molecular activity
GO:0005198 structural molecule activity 2 GO:0060090 molecular adaptor activity 2
Localization
GO:0005856 cytoskeleton 2
Pathway
R-HSA-1852241 Organelle biogenesis and maintenance 2
Partners
CCDC40
Complex memberships
CCDC39/CCDC40 molecular ruler complex

Evidence

Reading pass · 9 per-paper findings extracted from the source corpus
Year Finding Method Journal Conf PMIDs
2010 CCDC39 localizes to ciliary axonemes and is essential for assembly of inner dynein arms (IDAs) and the dynein regulatory complex (DRC). Loss-of-function mutations abolish this assembly, resulting in abnormal ciliary beating. Positional cloning in dogs, identification of human loss-of-function mutations, immunofluorescence localization to ciliary axonemes, functional analysis of ciliary motility Nature genetics High 21131972
2013 CCDC39 and CCDC40 are the two primary genes responsible for PCD with axonemal disorganization and IDA loss; all pathogenic mutations identified were null alleles (nonsense, splice, frameshift), indicating complete protein loss underlies the defect. Radial spoke structures are largely intact in these patients, clarifying that the ultrastructural defect is specifically IDA and microtubular disorganization. Sequencing of CCDC39 and CCDC40 in 54 families; transmission electron microscopy of ciliary ultrastructure Human mutation High 23255504
2012 CCDC39 mutations cause PCD with IDA defects and axonemal disorganization; the same ultrastructural defects are present in sperm flagella of affected males, demonstrating CCDC39 is required for flagellar as well as ciliary axonemal integrity. Sequencing of CCDC39 in patient cohort; quantitative ultrastructural analysis of cilia and sperm flagella by TEM Journal of medical genetics High 22693285
2018 Ccdc39 protein localizes to the axoneme of motile cilia in ependymal cells and choroid plexus; loss of Ccdc39 causes shorter ependymal cilia with disorganized microtubules and absent inner arm dynein, abolishing orchestrated ciliary beating and unidirectional CSF flow, leading to hydrocephalus. Whole-genome sequencing of prh mouse mutant; immunofluorescence localization; high-speed video microscopy of ciliary beating and CSF flow; TEM of cilia ultrastructure Development (Cambridge, England) High 29317443
2024 CCDC39 and CCDC40 form a molecular ruler complex that maintains 96 nm repeat units along ciliary axonemes. Disease-causing variants in CCDC39 cause axonemal absence of IDA heavy chains DNAH1, DNAH6, and DNAH7 (including centrin2-containing IDAs), as well as abnormal assembly of GAS8 and DNALI1, demonstrating that the CCDC39/CCDC40 ruler is required for assembly of specific IDA subtypes. Next-generation sequencing for variant identification; immunofluorescence analysis of respiratory ciliary axonemes in cohort of 51 individuals Cells Medium 39056782
2023 Pathogenic variants in CCDC39 cause absence or severe reduction of CCDC39 protein in sperm flagella, and this is accompanied by loss of CCDC40 in flagella of CCDC39-mutant individuals, revealing an interaction between CCDC39 and CCDC40 in sperm flagella (CCDC40 depends on CCDC39 for flagellar localization). Immunofluorescence microscopy on sperm flagella from patients with CCDC39 mutations; next-generation sequencing Frontiers in genetics Medium 36873931
2021 A missense loss-of-function mutation in CCDC39 (p.Leu328Pro) results in near-complete absence of CCDC39 protein in spermatozoa (confirmed by immunofluorescence and western blot) and causes multiple morphological abnormalities of sperm flagella (MMAF) alongside PCD, establishing CCDC39 as required for normal sperm flagella morphology. Whole-exome sequencing; transmission electron microscopy of sperm flagella; immunofluorescence staining; western blotting Reproductive biomedicine online Medium 34674941
2019 Loss of Ccdc39 in rats (via CRISPR/Cas9) causes progressive hydrocephalus with impaired glymphatic CSF flow along cerebral arteries; double mutants with L1cam gene mutation show accelerated early hydrocephalus, placing Ccdc39 in a genetic interaction with L1cam in CSF flow regulation. CRISPR/Cas9 knockin rat model; MRI imaging; glymphatic flow assessment; genetic epistasis with L1cam mutation Disease models & mechanisms Medium 31771992
2025 Conditional knockout of Ccdc39 specifically in adult ependymal cells causes transient ventricular enlargement and increased periventricular microglial density, demonstrating that CCDC39 function in ependymal motile cilia is specifically required for ventricular homeostasis in the adult brain. Conditional knockout mouse model targeting ependymal cells; MRI volumetry; immunohistochemistry bioRxivpreprint Low

Source papers

Stage 0 corpus · 17 papers · ranked by NIH iCite citations
Year Title Journal Citations PMID
2010 CCDC39 is required for assembly of inner dynein arms and the dynein regulatory complex and for normal ciliary motility in humans and dogs. Nature genetics 273 21131972
2013 Mutations in CCDC39 and CCDC40 are the major cause of primary ciliary dyskinesia with axonemal disorganization and absent inner dynein arms. Human mutation 158 23255504
2012 Delineation of CCDC39/CCDC40 mutation spectrum and associated phenotypes in primary ciliary dyskinesia. Journal of medical genetics 79 22693285
2018 A mutation in Ccdc39 causes neonatal hydrocephalus with abnormal motile cilia development in mice. Development (Cambridge, England) 64 29317443
2021 A novel CCDC39 mutation causes multiple morphological abnormalities of the flagella in a primary ciliary dyskinesia patient. Reproductive biomedicine online 29 34674941
2019 Impaired neural differentiation and glymphatic CSF flow in the Ccdc39 rat model of neonatal hydrocephalus: genetic interaction with L1cam. Disease models & mechanisms 28 31771992
2020 Neonatal hydrocephalus leads to white matter neuroinflammation and injury in the corpus callosum of Ccdc39 hydrocephalic mice. Journal of neurosurgery. Pediatrics 27 32032950
2023 Pathogenic gene variants in CCDC39, CCDC40, RSPH1, RSPH9, HYDIN, and SPEF2 cause defects of sperm flagella composition and male infertility. Frontiers in genetics 25 36873931
2020 Ultrastructural Sperm Flagellum Defects in a Patient With CCDC39 Compound Heterozygous Mutations and Primary Ciliary Dyskinesia/Situs Viscerum Inversus. Frontiers in genetics 12 33005176
2024 Primary Ciliary Dyskinesia Associated Disease-Causing Variants in CCDC39 and CCDC40 Cause Axonemal Absence of Inner Dynein Arm Heavy Chains DNAH1, DNAH6, and DNAH7. Cells 9 39056782
2022 Copy number variation of the CCDC39 gene is associated with growth traits in Chinese cattle. Veterinary medicine and science 7 35233959
2022 Biallelic Variants in CCDC39 Gene Lead to Primary Ciliary Dyskinesia and Kartagener Syndrome. BioMed research international 5 35795318
2023 Early postnatal microglial ablation in the Ccdc39 mouse model reveals adverse effects on brain development and in neonatal hydrocephalus. Fluids and barriers of the CNS 4 37296418
2024 Chronic Cough, Dyspnea, and a Novel CCDC39 Variant: A Case Report of Heterotaxy Syndrome Without Cardiac Anomalies and Associated Primary Ciliary Dyskinesia. Cureus 1 39867101
2026 A homozygous splicing mutation in CCDC39 caused multiple morphological abnormalities of the flagella in an infertile man with primary ciliary dyskinesia. Asian journal of andrology 0 42210652
2025 [Clinical and genetic analysis of a child with Primary ciliary dyskinesia variants and co-existence of CCDC39 gene variants and 22q11.21 deletion]. Zhonghua yi xue yi chuan xue za zhi = Zhonghua yixue yichuanxue zazhi = Chinese journal of medical genetics 0 40763972
2025 CCDC39 Mutation-Related Primary Ciliary Dyskinesia with Congenitally Corrected Transposition of the Great Arteries: A Case Report. The American journal of case reports 0 41082487

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