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Title | Mechanism of IFT-A polymerization into trains for ciliary transport. |
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Journal, issue, pages | Cell, Vol. 185, Issue 26, Page 4986-4998.e12, Year 2022 |
Publish date | Dec 22, 2022 |
Authors | Shimi Meleppattu / Haixia Zhou / Jin Dai / Miao Gui / Alan Brown / |
PubMed Abstract | Intraflagellar transport (IFT) is the highly conserved process by which proteins are transported along ciliary microtubules by a train-like polymeric assembly of IFT-A and IFT-B complexes. IFT-A is ...Intraflagellar transport (IFT) is the highly conserved process by which proteins are transported along ciliary microtubules by a train-like polymeric assembly of IFT-A and IFT-B complexes. IFT-A is sandwiched between IFT-B and the ciliary membrane, consistent with its putative role in transporting transmembrane and membrane-associated cargoes. Here, we have used single-particle analysis electron cryomicroscopy (cryo-EM) to determine structures of native IFT-A complexes. We show that subcomplex rearrangements enable IFT-A to polymerize laterally on anterograde IFT trains, revealing a cooperative assembly mechanism. Surprisingly, we discover that binding of IFT-A to IFT-B shields the preferred lipid-binding interface from the ciliary membrane but orients an interconnected network of β-propeller domains with the capacity to accommodate diverse cargoes toward the ciliary membrane. This work provides a mechanistic basis for understanding IFT-train assembly and cargo interactions. |
External links | Cell / PubMed:36563665 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.4 - 3.5 Å |
Structure data | EMDB-28866, PDB-8f5o: EMDB-28867, PDB-8f5p: |
Chemicals | ChemComp-ZN: |
Source |
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Keywords | PROTEIN TRANSPORT / Cilia / IFT |