GoKawiilRNF213 enzyme found to tag defective glycogen for cellular disposal
Researchers identified RNF213, an E3 ubiquitin ligase, as a key surveillance mechanism that marks poorly branched, disease-causing glycogen (polyglucosan) for destruction via autophagy. Mice lacking RNF213's ligase activity built up polyglucosan deposits in the cerebellum, pons, and hippocampus, and cell studies showed the enzyme selectively ubiquitylates abnormal glycogen while a structural domain restrains it from attacking healthy glycogen. Once tagged, the aberrant glycogen recruits autophagy receptors SQSTM1, TAX1BP1, and optineurin, which shuttle it into autophagosomes for clearance.
GoKawiil's interpretation of the reporting above, not reported fact.
This is the first evidence that cells apply ubiquitin-based quality control not just to proteins but directly to a carbohydrate molecule, expanding the known scope of cellular surveillance systems. Because polyglucosan buildup underlies severe neurological diseases, understanding RNF213's role could open new therapeutic angles for disorders involving glycogen storage defects and possibly inform research into RNF213's other known disease links, such as stroke risk.
- RNF213 directly ubiquitylates abnormal glycogen, marking it for autophagic clearance.
- Its CBM20 carbohydrate-binding domain normally restrains the enzyme from attacking healthy glycogen.
- Loss of RNF213 ligase activity causes polyglucosan buildup in mouse brain regions, implicating it in neurological disease prevention.
Source: nature.com — Yip, 2026-09-15
Published there as: “Quality control of glycogen through direct ubiquitylation by RNF213”
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