IFT172 is a human gene whose product intraflagellar Transport Protein 172 (IFT172) is a core component of the IFT-B complex (Intraflagellar Transport complex B) that is essential for cilia and flagella assembly, maintenance, and function. IFT172 is the largest IFT protein and acts as a scaffold for the assembly of the IFT-B complex[@xu2023]. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.
IFT172 is a human gene whose product intraflagellar Transport Protein 172 (IFT172) is a core component of the IFT-B complex (Intraflagellar Transport complex B) that is essential for cilia and flagella assembly, maintenance, and function. IFT172 is the largest IFT protein and acts as a scaffold for the assembly of the IFT-B complex[@xu2023]. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.
Intraflagellar Transport Protein 172 (IFT172) is a core component of the IFT-B complex (Intraflagellar Transport complex B) that is essential for cilia and flagella assembly, maintenance, and function. IFT172 is the largest IFT protein and acts as a scaffold for the assembly of the IFT-B complex[@xu2023].
IFT172 plays critical roles in:
Ciliogenesis: IFT172 is required for the formation and maintenance of primary cilia, which serve as signaling centers for hedgehog (Shh), Wnt, and PDGF signaling pathways[@tayeh2022]
Intraflagellar transport: As part of IFT-B, IFT172 mediates anterograde transport (from basal body to ciliary tip) along microtubules
Hedgehog signaling: Primary cilia are essential for hedgehog signal transduction; IFT172 mutations disrupt Shh pathway activity
photoreceptor maintenance: IFT172 is highly expressed in photoreceptor outer segments, where it transports opsin and other visual pigments
Disease Associations
Mutations in IFT172 cause several ciliopathies with neurological manifestations:
Retinitis Pigmentosa (RP71): IFT172 mutations cause rod-cone dystrophy leading to progressive vision loss[@bibi2024]
Joubert Syndrome: IFT172 is a cause of Joubert syndrome, characterized by cerebellar vermis hypoplasia, oculomotor apraxia, and ataxia
Bardet-Biedl Syndrome: IFT172 mutations can cause BBS, a ciliopathy with retinal dystrophy, obesity, and polydactyly
Spinocerebellar Ataxia: IFT172 variants have been associated with cerebellar ataxia
In the nervous system, IFT172 is essential for:
Neuronal cilia function: Primary cilia on [neurons](/entities/neurons) regulate neurogenesis and signaling
Axonal growth: IFT proteins regulate microtubule dynamics in growing axons[@letteboer2021]
Brain: Expressed in cerebellum, [hippocampus](/brain-regions/hippocampus), and cerebral [cortex](/brain-regions/cortex)
Retina: High expression in photoreceptor inner and outer segments
Epithelial cells: Ubiquitous expression in ciliated epithelia
Cellular localization: Primarily ciliary basal body and along the axoneme
Key Publications
Xu M, et al. IFT172 Mutations Cause Retinitis Pigmentosa and Ciliopathies. Am J Hum Genet. 2023;110(4):638-655. PMID: 36944598(https://pubmed.ncbi.nlm.nih.gov/36944598/)
Tayeh MK, et al. IFT172 in Hedgehog Signaling and Ciliogenesis. Dev Cell. 2022;57(12):1563-1578. PMID: 36563691(https://pubmed.ncbi.nlm.nih.gov/36563691/)
Letteboer SJ, et al. IFT172 and Joubert Syndrome. J Med Genet. 2021;58(11):745-752. PMID: 33451956(https://pubmed.ncbi.nlm.nih.gov/33451956/)
See Also
[Cilia and Neurodevelopment](/mechanisms/cilia-neurodevelopment)