1.X.1.  The Intraflagellar Transporter-A Complex (Ift-A) Family

The Ift-A complex appears to be a multicomponent complex that functions to transport flagellar/ciliary membrane proteins under the eukaryotic ciliary membrane.  As a component of the IFT complex A (IFT-A), a complex required for retrograde ciliary transport and entry into cilia of G protein-coupled receptors (GPCRs), it is involved in ciliogenesis and ciliary protein trafficking (Mill et al. 2011, Duran et al. 2017, Takahara et al. 2018). Not all of the ItfA complex have been identified.  Here, we list only a few of them.


 

References:

Duran, I., S.P. Taylor, W. Zhang, J. Martin, F. Qureshi, S.M. Jacques, R. Wallerstein, R.S. Lachman, D.A. Nickerson, M. Bamshad, D.H. Cohn, and D. Krakow. (2017). Mutations in IFT-A satellite core component genes and produce short rib polydactyly syndrome with distinctive campomelia. Cilia 6: 7.

Lechtreck, K. (2022). Cargo adapters expand the transport range of intraflagellar transport. J Cell Sci 135:.

Mill, P., P.J. Lockhart, E. Fitzpatrick, H.S. Mountford, E.A. Hall, M.A. Reijns, M. Keighren, M. Bahlo, C.J. Bromhead, P. Budd, S. Aftimos, M.B. Delatycki, R. Savarirayan, I.J. Jackson, and D.J. Amor. (2011). Human and mouse mutations in WDR35 cause short-rib polydactyly syndromes due to abnormal ciliogenesis. Am J Hum Genet 88: 508-515.

Takahara, M., Y. Katoh, K. Nakamura, T. Hirano, M. Sugawa, Y. Tsurumi, and K. Nakayama. (2018). Ciliopathy-associated mutations of IFT122 impair ciliary protein trafficking but not ciliogenesis. Hum Mol Genet 27: 516-528.

Werner, S., P. Okenve-Ramos, P. Hehlert, S. Zitouni, P. Priya, S. Mendonça, A. Sporbert, C. Spalthoff, M.C. Göpfert, S.C. Jana, and M. Bettencourt-Dias. (2024). IFT88 maintains sensory function by localising signalling proteins along cilia. Life Sci Alliance 7:.

Examples:

TC#NameOrganismal TypeExample
1.X.1.1.1

The Intraflagellar transporter (IFT) multiprotein complex. WD repeat-containing protein 35 of 1181 aas and possibly as many as 7 or 8 TMSs. It is a component of the IFT complex A (IFT-A), a complex required for retrograde ciliary transport and entry into cilia of G protein-coupled receptors (GPCRs). It is thus involved in ciliogenesis and ciliary protein trafficking (Takahara et al. 2018) (see the family description). Many other proteins play a role as constituents of the IFT complex, and some of these (but not all of them) are listed under this TC# (Lechtreck 2022).

IFT complex of Homo sapiens
WD repeat protein 35 of 1181 aas, Q9P2L0
IFT dynein (part of the motor) of 1066 aas, Q8WVS4
IFT kinesin-2, IFT88, 824 aas, Q13099
IFT25/27 adaptor, 186 aas, (adaptor for cargo BBSome), Q9BW83
IFT56, 554 aas (adaptor for cargo IDA3), A0AVF1
IFT46, 304 aas (adaptor for cargo ODA16), Q9NQC8
IFT81, 676 aas (adaptor for cargo alpha), Q8WYA0
IFT74, 600 aas (adaptor for cargo beta), Q96LB3
IFT122, 1241 aas (adaptor for cargo TULP3), Q9HBG6

 
1.X.1.1.2

The sensory ciliary function underlying hearing in the adult fly requires an active maintenance program which involves DmIFT88 and at least two of its signalling transmembrane cargoes, DmGucy2d and Inactive (Werner et al. 2024).

Complex of three proteins of Drosophila melanogaster