RIBC2: a ciliary protein candidate in a non-ciliated methylation story
The signal
The highlighted UC study found RIBC2 promoter hypermethylation and reduced transcript abundance Kang et al..
The UC evidence is one small discovery/technical-validation pipeline: 8 UC and 3 control tissues on 450K arrays, targeted testing in 79 UC samples, and bulk transcript measurement (Kang, Bae, Han, Kim, Kim, and Yi, 2016). It supports a reproducible locus within that study, not a validated cilia mechanism or clinical test.
RIBC2 present
In vertebrate model work, Ribc2 localizes to motile-cilia axonemes and supports organized beating.
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Ribc2 disrupted
Xenopus experiments showed disorganized axonemes and impaired ciliary beating.
The functional evidence comes from an RFX2 ciliogenesis study, not UC colon. The ordinary colonic surface epithelium is not a classic motile-ciliated tissue, so importing that phenotype directly would be misleading. RIBC2 may mark a cell population, have a different intracellular role, or be an epigenetic passenger here.
In the cited Xenopus work, RIBC2 was an RFX2-dependent multiciliated-cell gene; knockdown disrupted axonemal organization and ciliary beating (Chung, Kwon, Tu, Brooks, Gupta, Meyer, Baker, Marcotte, and Wallingford, 2014). That is valuable functional evidence with a sharp tissue boundary. Its best use here is to generate localization experiments, not to fill an unobserved step in UC pathogenesis.
If expression stops in this context
The answer remains unknown. Confirm which colonic cells express RIBC2, whether the protein is present, and whether promoter methylation explains within-cell repression. A methylation biomarker can be useful even when its encoded protein is not mechanistically central.