{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nThe study detailed in the abstract"}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "uncovers the critical role of TTC19 in the mitochondrial respiratory chain, specifically in the maturation and maintenance of complex III. TTC19 binds to the fully assembled complex III dimer after the incorporation of the Rieske iron‐sulfur protein (UQCRFS1), and the protein’s presence is essential for removing the N‑terminal fragments generated during UQCRFS1’s in situ maturation.\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn normal mitochondrial biogenesis, the rapid removal of these UQCRFS1 fragments is key to preserving complex III’s structural integrity and enzymatic function. However, in both the Ttc19?/? mouse model and human cell lines, the absence of TTC19 results in the accumulation of these N‑terminal polypeptides. This accumulation impairs the structure and function of complex III, ultimately leading to decreased complex III activity and an increase in reactive oxygen species.\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nThe resulting mitochondrial dysfunction in the absence of TTC19 manifests in severe neurological and metabolic decline. Although the question initially asked for a summary of SNORD121B function, the provided abstract does not address SNORD121B; instead, it provides detailed insight into TTC19’s mechanism in complex III biogenesis and its broader impact on mitochondrial and cellular health."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Emanuela Bottani, Raffaele Cerutti, Michael E Harbour, et al. "}, {"type": "b", "children": [{"type": "t", "text": "TTC19 Plays a Husbandry Role on UQCRFS1 Turnover in the Biogenesis of Mitochondrial Respiratory Complex III."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Cell (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.molcel.2017.06.001"}], "href": "https://doi.org/10.1016/j.molcel.2017.06.001"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "28673544"}], "href": "https://pubmed.ncbi.nlm.nih.gov/28673544"}]}]}]}