biostudies-literatureJetishi CSwiss National Science FoundationWellcome Truste1013521https://www.ebi.ac.uk/biostudies/studies/S-EPMC12453217biostudies-literatureUnknown21(9)The Tripartite Attachment Complex (TAC) is essential for mitochondrial DNA (kDNA) segregation in Trypanosoma brucei, providing a physical link between the flagellar basal body and the mitochondrial genome. Although the TAC's hierarchical assembly and linear organization have been extensively studied, much remains to be discovered regarding its complete architecture and composition - for instance, our identification of a new TAC component underscores these knowledge gaps. Here, we use a combination of proteomics, RNA interference (RNAi), and Ultrastructure Expansion Microscopy (U-ExM) to characterize the TAC at high resolution and identify a novel component, TAC53 (Tb927.2.6100). Depletion of TAC53 in both procyclic and bloodstream forms results in kDNA missegregation and loss, a characteriPLoS pathogensConnecting basal body and mitochondrial DNA: TAC53 and the tubular organization of the tripartite attachment complex.PMC12453217205200227243/Z/23/Z207525205601179454Kaser SSchimanski BJetishi CSchneider AOchsenreiter TOeljeklaus SAeschlimann SWarscheid BMullner RAkiyoshi BButter FfalseConnecting basal body and mitochondrial DNA: TAC53 and the tubular organization of the tripartite attachment complex.The Tripartite Attachment Complex (TAC) is essential for mitochondrial DNA (kDNA) segregation in Trypanosoma brucei, providing a physical link between the flagellar basal body and the mitochondrial genome. Although the TAC's hierarchical assembly and linear organization have been extensively studied, much remains to be discovered regarding its complete architecture and composition - for instance, our identification of a new TAC component underscores these knowledge gaps. Here, we use a combination of proteomics, RNA interference (RNAi), and Ultrastructure Expansion Microscopy (U-ExM) to characterize the TAC at high resolution and identify a novel component, TAC53 (Tb927.2.6100). Depletion of TAC53 in both procyclic and bloodstream forms results in kDNA missegregation and loss, a characteri2025-01-01T00:00:00Z2025 Sep2026-04-30T03:20:48.636Z2026-04-30T03:12:09.332ZS-EPMC124532174095312510.1371/journal.ppat.1013521