A Nature paper dated 15 September 2026 reports that the E3 ligase RNF213 puts ubiquitin directly on poorly branched glycogen, a check against polyglucosan piles in the brain. Mice whose ligase work had stopped piled polyglucosan in cerebellum, pons and hippocampus. Science and New Scientist pages checked on 15 September did not carry their own matching write-up.
The Nature paper is dated 15 September 2026. Polyglucosan bodies are insoluble heaps of weakly branched glycogen and are linked to severe disease. Mice whose ligase work had stopped piled those heaps in cerebellum, pons and hippocampus. In cells built to make polyglucosan, the same ligase put ubiquitin on the abnormal glycogen with selectivity. The card does not treat this as a human therapy or a diagnostic-test launch. The mechanism is mouse and cell.[1]
A cryo-electron view shows the CBM20 piece holding maltoheptaose derived from glycogen. When that hold is broken, activity toward ordinary physiological glycogen rises. An epistasis experiment places RNF213 upstream of LUBAC. Ubiquitin-tagged polyglucosan pulls SQSTM1, TAX1BP1 and optineurin into autophagosomes. The writers read this as non-protein ubiquitylation that protects glycogen quality in astrocytes. That the same chain is already proven in human tissue is not this paper’s claim.[1]
RNF213’s mark on weakly branched glycogen and the mouse pile-up sit in the same Nature paper. Science and New Scientist pages and feeds on 15 September did not carry their own matching write-up. The card does not say polyglucosan diseases are over. The finding is ligase and glycogen. The second-publisher check was empty. The same paper keeps the CBM20 hold and the LUBAC order inside that mechanism file. There is no human clinical trial here.[1]
