CFAP97D2

Model summary

A human cilia-associated scaffold that concentrates in the axoneme and uses multivalent protein binding to organize axonemal assemblies. By stabilizing microtubule-associated complexes within the ciliary core and cytoskeletal framework, it supports mechanosensory pathways of the inner ear and thereby contributes to hearing. Its soluble nature and assembly onto cytoskeletal structures explain its presence in the cytoplasm and cytoskeleton, with functional enrichment at the axoneme where it coordinates axonemal architecture.

Predicted Gene Ontology terms

1. 01

   I begin with the InterPro architecture.

   The N-terminus (residues 1–96) is assigned to IPR038792 (CFAP97 domain-containing protein 1/2 family), and within this region lies IPR029488 (Hemingway/CFA97 family) spanning residues 27–94. This tandem of CFAP97/Hemingway-family signatures defines a conserved cilia-associated scaffold module rather than an enzyme. The compact, coiled-coil–rich architecture typical of CFAP97 families promotes multivalent protein–protein interactions and assembly into axonemal complexes. The absence of catalytic motifs and the dominance of interaction-prone family signatures causally point to a molecular function centered on GO:0005515 protein binding.

2. 02

   From this binding-centric core, I infer the biological role by considering where such scaffolds act.

   CFAP97/Hemingway modules are enriched in ciliary systems and are repeatedly implicated in organizing axonemal and transition-zone assemblies. This places the protein within the ciliary apparatus that underlies mechanosensory and motile signaling. In the inner ear, hair-cell bundles and associated ciliary structures transduce mechanical stimuli into electrical signals; defects in their assembly manifest as hearing loss. Therefore, a binding scaffold that stabilizes or regulates axonemal architecture directly supports GO:0007605 sensory perception of sound.

3. 03

   The cellular context follows from the same architecture.

   CFAP97-family scaffolds typically localize to the axoneme—the microtubule-based core of cilia and flagella—where they coordinate dynein arms, radial spokes, and accessory structures. This reasoning anchors the protein to GO:0005930 axoneme. The experimentally observed presence in cytoplasm and cytoskeleton is consistent with a soluble scaffold that assembles onto cytoskeletal frameworks before concentrating within the axonemal core.

4. 04

   Mechanistically, I hypothesize that the CFAP97/Hemingway module nucleates higher-order assemblies that tune axonemal integrity and signaling.

   By binding multiple axonemal partners, it likely stabilizes microtubule-associated complexes and modulates mechanochemical coupling essential for auditory transduction. Candidate partners include tubulin heterodimers and axonemal regulators (e.g., dynein-associated factors and radial spoke proteins), whose coordinated assembly explains how this scaffold influences hearing. In sum, the CFAP97/Hemingway architecture causes a multivalent protein-binding activity that organizes axonemal machinery, thereby enabling auditory sensory pathways and localizing to the axoneme within the cytoskeletal compartment.