IFT172 — intraflagellar transport 172
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. This page covers the gene's normal function, disease associations, expression patterns, and key research findings relevant to neurodegeneration.
Full NameIntraflagellar Transport Protein 172
SymbolIFT172
Chromosomal LocationChromosome 2 (2p23.3)
NCBI Gene ID[26160](https://www.ncbi.nlm.nih.gov/gene/26160)
OMIM[607386](https://www.omim.org/entry/607386)
Ensembl ID[ENSG00000124608](https://www.ensembl.org/Homo_sapiens/Gene/Summary?g=ENSG00000124608)
UniProt ID[Q9H7E9](https://www.uniprot.org/uniprot/Q9H7E9)
Associated Diseases[Retinitis Pigmentosa](/diseases/retinitis-pigmentosa), [Joubert Syndrome](/diseases/joubert-syndrome), [Bardet-Biedl Syndrome](/diseases/bardet-biedl-syndrome), [Spinocerebellar Ataxia](/diseases/spinocerebellar-ataxia)
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.
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
- 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
Mutations in IFT172 cause several ciliopathies with neurological manifestations:
- Retinitis Pigmentosa (RP71): IFT172 mutations cause rod-cone dystrophy leading to progressive vision loss
- 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 regulate neurogenesis and signaling
- Axonal growth: IFT proteins regulate microtubule dynamics in growing axons
- Synaptic function: Ciliary signaling pathways modulate synaptic plasticity
IFT172 has tissue-specific expression:
- Brain: Expressed in cerebellum, hippocampus, and cerebral 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
- Xu M, et al. IFT172 Mutations Cause Retinitis Pigmentosa and Ciliopathies. Am J Hum Genet. 2023;110(4):638-655. PMID:36944598
- Tayeh MK, et al. IFT172 in Hedgehog Signaling and Ciliogenesis. Dev Cell. 2022;57(12):1563-1578. PMID:36563691
- Letteboer SJ, et al. IFT172 and Joubert Syndrome. J Med Genet. 2021;58(11):745-752. PMID:33451956