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Subcellular localization

cilia, Vesicles, Plasma membrane, Centrosome

Functional category

• Metabolism
• Motile cilium & axoneme
• Ciliary assembly/disassembly
• Cilia–cytoskeleton/adhesion links

Function

We combined biochemical, genetic, and structural analyses to investigate the protein composition and molecular organization of a group of interconnected CA projections, here termed the C1a-e-c supercomplex, in WT and CA mutants of Chlamydomonas. Sucrose gradient sedimentation and MS revealed that several CA proteins identified in this study, flagellar associated protein 76 (FAP76), FAP81, FAP92, and FAP216, are associated with the protein PF16, previously assigned to the C1 microtubule but not to a specific projection. Chlamydomonas mutants that lacked any of these proteins showed impaired motility. Structural comparisons of flagella from WT, these mutants, and tagged rescue strains revealed the precise locations of PF16, FAP76, FAP81, FAP92, and FAP216 within the C1a-e-c supercomplex. Our data show that stable assembly of this supercomplex and its interaction with the neighboring C1d projection are required for the proper regulation of ciliary motility.