Pathway Human Homo sapiens

Intraflagellar transport

R-HSA-5620924 in Reactome release 97: under Assembly of the 9+0 primary cilium, with 54 genes placed in it by the mapping files and 0 child pathways in the hierarchy.

The same number in the other species

Reactome writes the mouse and rat events it infers from a human pathway under the human number with the species token. A door opens only where that species' own list in this release holds the id: R-MMU-5620924 (mouse), R-RNO-5620924 (rat). Whether the event was inferred from this one is what the record says.

The record
The genes
Parents and children

Scripts are off

This page reads the pathway's record from its source while you read the rest; with scripts off the card stays at its loading line. Reload with scripts on to see it, or open the source's own page from the link in the card.

01The record

Reactome's own record of this pathway

What this tells you

The pathway list, the hierarchy and the genes on this page are read from the files Reactome publishes for Reactome release 97, built into this site on 2026-09-09: the pathway list, the hierarchy relationship file and the two gene mapping files. The record card is the one live read, Reactome's own record of this pathway.

Reactome's download page describes the mapping files: Mapping files link the source database identifier to the lowest level pathway diagram or subset of the pathway, all levels of the pathway hierarchy or database identifier to all reactions. [R13] The gene list here is the all-levels mapping of NCBI Gene ids, filled from the all-levels mapping of Ensembl ids where the NCBI file has no row for a gene; each row names which file it came from by the shape of its source id. Each row carries the evidence codes the file writes for it, as written and unranked, and both where the file writes both; no page of Reactome's documentation the survey read defines the codes, so this page does not expand them. A gene id the identity files do not name is kept as the source's own id with no door rather than turned into a symbol.

On citing what a search finds, Reactome says: It should be remembered that while we strive to contain the most current and accurate data, Reactome should not be used in citations where other primary sources of information are available. [R12] The record card prints the literature Reactome attaches to a curated pathway for that reason. The data are public domain: All data in the Reactome database and files derived from that data are licensed under the Creative Commons Public Domain Dedication (CC0). User may copy, modify, and distribute these data, even for commercial purposes, without asking for permission. Attribution is encouraged but not required. [R10] The pathway illustrations are licensed apart, under CC BY 4.0, and none is shown here.

A gene on this list is one Reactome places in this pathway in this release, and that is all the row says: it does not say the gene is expressed in a tissue or associated with a disease, which are the other two explorers' questions, read from other sources. Reactome's papers of record are [R01] [R02].

[R01] Ragueneau E, Gong C, Sinquin P, Sevilla C, Beavers D, Grentner A, et al. (2026). The Reactome Knowledgebase 2026. Nucleic Acids Research 54:D673-D681. PMID 41251150, doi 10.1093/nar/gkaf1223.
[R02] Milacic M, Beavers D, Conley P, Gong C, Gillespie M, Griss J, et al. (2024). The Reactome Pathway Knowledgebase 2024. Nucleic Acids Research 52:D672-D678. PMID 37941124, doi 10.1093/nar/gkad1025.
[R10] Reactome, reactome.org. License Agreement. https://reactome.org/license, read 2026-09-09.
[R12] Reactome, reactome.org. Citing us. https://reactome.org/cite, read 2026-09-09.
[R13] Reactome, reactome.org. Download. https://reactome.org/download-data, read 2026-09-09.

Stable id: R-HSA-5620924.5
Class: Pathway
Species: Homo sapiens (human)
Inferred: no: a curated human pathway
Disease pathway: no
Released: 2014-12-11
Last updated: 2016-12-21
Events inside: 12, counted from the record

Intraflagellar transport (IFT) is a motor-based process that controls the anterograde and retrograde transport of large protein complexes, ciliary cargo and structural components along the ciliary axoneme (reviewed in Cole and Snell, 2009). IFT particles contain two multiprotein IFT subcomplexes, IFT A and IFT B, with ~6 and ~15 subunits, respectively. Linear arrays of IFT A and IFT B 'trains' assemble at the ciliary base along with the active plus-end directed kinesin-2 motors and the inactive dynein motors and traffic along the microtubules at a rate of ~2 micrometers per second. At the ciliary tip, the IFT trains disassemble, releasing cargo and motors, and smaller IFT trains are subsequently reassembled for retrograde traffic driven by the now active minus-end directed dynein-2 motors. Retrograde trains travel down the length of the axoneme at a rate of ~3 micrometers per second and are disassembled and recycled for further rounds of transport at the ciliary base (reviewed in Taschner et al, 2012; Bhogaraju et al, 2013; Ishikawa et al, 2011). Mutations in kinesin-2 motors or IFT B complex members tend to abrogate cilium formation, while mutations in dynein-2 motor or in IFT A complex members generally result in short, bulging cilia that abnormally accumulate IFT particles. These observations are consistent with a primary role for IFT B and IFT A complexes in anterograde and retrograde transport, respectively (see for instance, Huangfu et al, 2005; Follit et al, 2006; May et al, 2005; Tran et al, 2008; reviewed in Ishikawa et al, 2011). In addition to the IFT A and B complexes, the IFT particles may also contain the multi-protein BBSome complex, which displays typical IFT-like movement along the ciliary axoneme and which is required for cilium biogenesis and delivery and transport of some ciliary cargo (Blaque et al, 2004; Nachury et al, 2007; Ou et al, 2005; Ou et al, 2007; reviewed in Sung and Leroux, 2013; Bhorgaraju et al, 2013).

Literature Reactome attaches

SnapShot: Intraflagellar transportCell, 2009, vol. 137, p. 784-784.e1PubMed 19450523
Architecture and function of IFT complex proteins in ciliogenesisDifferentiation, 2012, vol. 83, p. S12-22PubMed 22118932
Intraflagellar transport complex structure and cargo interactionsCilia, 2013, vol. 2, p. 10PubMed 23945166
Ciliogenesis: building the cell's antennaNat. Rev. Mol. Cell Biol., 2011, vol. 12, p. 222-34PubMed 21427764
Cilia and Hedgehog responsiveness in the mouseProc. Natl. Acad. Sci. U.S.A., 2005, vol. 102, p. 11325-30PubMed 16061793
The intraflagellar transport protein IFT20 is associated with the Golgi complex and is required for cilia assemblyMol. Biol. Cell, 2006, vol. 17, p. 3781-92PubMed 16775004
Loss of the retrograde motor for IFT disrupts localization of Smo to cilia and prevents the expression of both activator and repressor functions of GliDev. Biol., 2005, vol. 287, p. 378-89PubMed 16229832
THM1 negatively modulates mouse sonic hedgehog signal transduction and affects retrograde intraflagellar transport in ciliaNat. Genet., 2008, vol. 40, p. 403-10PubMed 18327258
Loss of C. elegans BBS-7 and BBS-8 protein function results in cilia defects and compromised intraflagellar transportGenes Dev., 2004, vol. 18, p. 1630-42PubMed 15231740
A core complex of BBS proteins cooperates with the GTPase Rab8 to promote ciliary membrane biogenesisCell, 2007, vol. 129, p. 1201-13PubMed 17574030
Functional coordination of intraflagellar transport motorsNature, 2005, vol. 436, p. 583-7PubMed 16049494
Sensory ciliogenesis in Caenorhabditis elegans: assignment of IFT components into distinct modules based on transport and phenotypic profilesMol. Biol. Cell, 2007, vol. 18, p. 1554-69PubMed 17314406
The roles of evolutionarily conserved functional modules in cilia-related traffickingNat. Cell Biol., 2013, vol. 15, p. 1387-97PubMed 24296415

Reactome's record lists 10 orthologous events, R-RNO-5620924 (Rattus norvegicus), R-MMU-5620924 (Mus musculus) among the species this site serves, and 8 in species this site opens no page for.

Reactome ContentService, this pathway's record · Reactome v97 · read 2026-10-01 ET · Reactome pathway browser"Intraflagellar transport". Reactome, release 97, https://reactome.org/PathwayBrowser/#/R-HSA-5620924 with StableID: R-HSA-5620924.5 (accessed 2026-10-01 ET). Reactome version 97 (CC0).

Reading this pathway's record from Reactome (the pathway record).Still reading. A first read of a pathway can take a while; this page waits up to 35 seconds for it, and its scripts then bring in the panel, or a line saying what did not arrive.

02The genes

Genes Reactome places in this human pathway

The mapping files place 54 genes in this human pathway; showing 1 to 54, in pages of 100, sorted by symbol for reading. The order carries no ranking.

Genes Reactome places in this human pathway, page 1 of 1
Gene	Authority id	Mapping file id	Evidence codes
GeneDYNC2H1	AuthorityHGNC:2962	Mapping file id79659 NCBI file	EvidenceTAS
GeneDYNC2I1	AuthorityHGNC:21862	Mapping file id55112 NCBI file	EvidenceTAS
GeneDYNC2I2	AuthorityHGNC:28296	Mapping file id89891 NCBI file	EvidenceTAS
GeneDYNC2LI1	AuthorityHGNC:24595	Mapping file id51626 NCBI file	EvidenceTAS
GeneDYNLL1	AuthorityHGNC:15476	Mapping file id8655 NCBI file	EvidenceTAS
GeneDYNLL2	AuthorityHGNC:24596	Mapping file id140735 NCBI file	EvidenceTAS
GeneDYNLRB1	AuthorityHGNC:15468	Mapping file id83658 NCBI file	EvidenceTAS
GeneDYNLRB2	AuthorityHGNC:15467	Mapping file id83657 NCBI file	EvidenceTAS
GeneDYNLT2	AuthorityHGNC:11695	Mapping file id6991 NCBI file	EvidenceTAS
GeneDYNLT2B	AuthorityHGNC:28482	Mapping file id255758 NCBI file	EvidenceTAS
GeneDYNLT5	AuthorityHGNC:26882	Mapping file id200132 NCBI file	EvidenceTAS
GeneIFT122	AuthorityHGNC:13556	Mapping file id55764 NCBI file	EvidenceTAS
GeneIFT140	AuthorityHGNC:29077	Mapping file id9742 NCBI file	EvidenceTAS
GeneIFT172	AuthorityHGNC:30391	Mapping file id26160 NCBI file	EvidenceIEA, TAS
GeneIFT20	AuthorityHGNC:30989	Mapping file id90410 NCBI file	EvidenceIEA, TAS
GeneIFT22	AuthorityHGNC:21895	Mapping file id64792 NCBI file	EvidenceIEA, TAS
GeneIFT25	AuthorityHGNC:25019	Mapping file id51668 NCBI file	EvidenceIEA, TAS
GeneIFT27	AuthorityHGNC:18626	Mapping file id11020 NCBI file	EvidenceIEA, TAS
GeneIFT38	AuthorityHGNC:19009	Mapping file id23059 NCBI file	EvidenceIEA, TAS
GeneIFT43	AuthorityHGNC:29669	Mapping file id112752 NCBI file	EvidenceTAS
GeneIFT46	AuthorityHGNC:26146	Mapping file id56912 NCBI file	EvidenceIEA, TAS
GeneIFT52	AuthorityHGNC:15901	Mapping file id51098 NCBI file	EvidenceIEA, TAS
GeneIFT54	AuthorityHGNC:17861	Mapping file id26146 NCBI file	EvidenceIEA, TAS
GeneIFT56	AuthorityHGNC:21882	Mapping file id79989 NCBI file	EvidenceIEA, TAS
GeneIFT57	AuthorityHGNC:17367	Mapping file id55081 NCBI file	EvidenceIEA, TAS
GeneIFT70A	AuthorityHGNC:25853	Mapping file id92104 NCBI file	EvidenceIEA, TAS
GeneIFT70B	AuthorityHGNC:26425	Mapping file id150737 NCBI file	EvidenceIEA, TAS
GeneIFT74	AuthorityHGNC:21424	Mapping file id80173 NCBI file	EvidenceIEA, TAS
GeneIFT80	AuthorityHGNC:29262	Mapping file id57560 NCBI file	EvidenceIEA, TAS
GeneIFT81	AuthorityHGNC:14313	Mapping file id28981 NCBI file	EvidenceIEA, TAS
GeneIFT88	AuthorityHGNC:20606	Mapping file id8100 NCBI file	EvidenceIEA, TAS
GeneKIF17	AuthorityHGNC:19167	Mapping file id57576 NCBI file	EvidenceTAS
GeneKIF3A	AuthorityHGNC:6319	Mapping file id11127 NCBI file	EvidenceTAS
GeneKIF3B	AuthorityHGNC:6320	Mapping file id9371 NCBI file	EvidenceTAS
GeneKIF3C	AuthorityHGNC:6321	Mapping file id3797 NCBI file	EvidenceTAS
GeneKIFAP3	AuthorityHGNC:17060	Mapping file id22920 NCBI file	EvidenceTAS
GeneTNPO1	AuthorityHGNC:6401	Mapping file id3842 NCBI file	EvidenceTAS
GeneTRIP11	AuthorityHGNC:12305	Mapping file id9321 NCBI file	EvidenceTAS
GeneTTC21B	AuthorityHGNC:25660	Mapping file id79809 NCBI file	EvidenceTAS
GeneTUBA1A	AuthorityHGNC:20766	Mapping file id7846 NCBI file	EvidenceTAS
GeneTUBA1B	AuthorityHGNC:18809	Mapping file id10376 NCBI file	EvidenceTAS
GeneTUBA1C	AuthorityHGNC:20768	Mapping file id84790 NCBI file	EvidenceTAS
GeneTUBA3C	AuthorityHGNC:12408	Mapping file id7278 NCBI file	EvidenceTAS
GeneTUBA3D	AuthorityHGNC:24071	Mapping file id113457 NCBI file	EvidenceTAS
GeneTUBA4A	AuthorityHGNC:12407	Mapping file id7277 NCBI file	EvidenceTAS
GeneTUBB1	AuthorityHGNC:16257	Mapping file id81027 NCBI file	EvidenceTAS
GeneTUBB2A	AuthorityHGNC:12412	Mapping file id7280 NCBI file	EvidenceTAS
GeneTUBB2B	AuthorityHGNC:30829	Mapping file id347733 NCBI file	EvidenceTAS
GeneTUBB3	AuthorityHGNC:20772	Mapping file id10381 NCBI file	EvidenceTAS
GeneTUBB4A	AuthorityHGNC:20774	Mapping file id10382 NCBI file	EvidenceTAS
GeneTUBB4B	AuthorityHGNC:20771	Mapping file id10383 NCBI file	EvidenceTAS
GeneTUBB6	AuthorityHGNC:20776	Mapping file id84617 NCBI file	EvidenceTAS
GeneWDR19	AuthorityHGNC:18340	Mapping file id57728 NCBI file	EvidenceTAS
GeneWDR35	AuthorityHGNC:29250	Mapping file id57539 NCBI file	EvidenceTAS

Evidence codes on this page: IEA, TAS, as the mapping file writes them; a row carrying two was written twice by the file, once under each. The mapping file id says which file placed the gene: an NCBI Gene id from NCBI2Reactome_All_Levels.txt, an Ensembl gene id from Ensembl2Reactome_All_Levels.txt. The two files can disagree about a code, so a row's codes are the one file's view. Measured by this site's build over this release on 2026-09-09: of the 138,908 human pathway-gene pairs both files place, 207 (0.149 per cent, over 47 genes) carry TAS in the Ensembl file where the NCBI rows carry IEA alone.

Reactome mapping files, the human rows for this pathway · Reactome release 97 · read 2026-09-09 · Reactome downloads"NCBI2Reactome_All_Levels.txt" and "Ensembl2Reactome_All_Levels.txt", Reactome, release 97, https://reactome.org/download-data/ (date of access 2026-09-09). Data CC0; attribution encouraged.

03The hierarchy

Parents and children in this release's hierarchy

Parents

Assembly of the 9+0 primary ciliumR-HSA-9975921201 genes

Children

None: no pathway of this release's list names this one as a parent.

Reactome's hierarchy is a graph rather than a tree: a pathway can sit under more than one parent, and the gene counts are each pathway's own placements at every level under it, so a parent's count is not the sum of its children's.

Reactome, the human pathway list and hierarchy relationship file · Reactome release 97 · read 2026-09-09 · Reactome downloads"ReactomePathways.txt" and "ReactomePathwaysRelation.txt", Reactome, release 97, https://reactome.org/download-data/ (date of access 2026-09-09). Data CC0; attribution encouraged.