Kinesins are motor proteins found in all eukaryotic lineages that move along microtubules to mediate cellular processes such as mitosis and intracellular transport. In trypanosomatids, the kinesin superfamily has undergone a prominent expansion, resulting in one of the most diverse kinesin repertoires that includes the two kinetoplastid-restricted families X1 and X2. Here, we characterize in Trypanosoma brucei TbKifX2A, an orphaned X2 kinesin. TbKifX2A tightly interacts with TbPH1, a kinesin-like protein with a likely inactive motor domain, a rarely reported occurrence. Both TbKifX2A and TbPH1 localize to the microtubule quartet (MtQ), a characteristic but poorly understood cytoskeletal structure that wraps around the flagellar pocket as it extends to the cell body anterior. The proximal proteome of TbPH1 revealed two other interacting proteins, the flagellar pocket protein FP45 and intriguingly another X2 kinesin, TbKifX2C. Simultaneous ablation of TbKifX2A/TbPH1 results in the depletion of FP45 and TbKifX2C and also an expansion of the flagellar pocket, among other morphological defects. TbKifX2A is the first motor protein to be localized to the MtQ. The observation that TbKifX2C also associates with the MtQ suggests that the X2 kinesin family may have co-evolved with the MtQ, both kinetoplastid-specific traits.

• Klíčová slova
• Trypanosoma, cytoskeleton, kinesin, microtubule quartet, microtubules, morphogenesis,
• MeSH
• cytoskelet metabolismus   MeSH
• kineziny * genetika   metabolismus   MeSH
• mikrotubuly metabolismus   MeSH
• PH-doména MeSH
• protozoální proteiny * genetika   metabolismus   MeSH
• Trypanosoma brucei brucei * metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• kineziny * MeSH
• protozoální proteiny * MeSH

• MeSH
• antibakteriální látky toxicita   MeSH
• antibiotická rezistence fyziologie   MeSH
• mitochondrie účinky léků   MeSH
• proteosyntéza účinky léků   MeSH
• tetracyklin toxicita   MeSH
• Trypanosoma účinky léků   fyziologie   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• antibakteriální látky MeSH
• tetracyklin MeSH

There are a variety of complex metabolic processes ongoing simultaneously in the single, large mitochondrion of Trypanosoma brucei. Understanding the organellar environment and dynamics of mitochondrial proteins requires quantitative measurement in vivo. In this study, we have validated a method for immobilizing both procyclic stage (PS) and bloodstream stage (BS) T. brucei brucei with a high level of cell viability over several hours and verified its suitability for undertaking fluorescence recovery after photobleaching (FRAP), with mitochondrion-targeted yellow fluorescent protein (YFP). Next, we used this method for comparative analysis of the translational diffusion of mitochondrial RNA-binding protein 1 (MRP1) in the BS and in T. b. evansi. The latter flagellate is like petite mutant Saccharomyces cerevisiae because it lacks organelle-encoded nucleic acids. FRAP measurement of YFP-tagged MRP1 in both cell lines illuminated from a new perspective how the absence or presence of RNA affects proteins involved in mitochondrial RNA metabolism. This work represents the first attempt to examine this process in live trypanosomes.

• MeSH
• mitochondriální proteiny genetika   MeSH
• mutace MeSH
• proteiny vázající RNA genetika   metabolismus   MeSH
• protozoální proteiny genetika   metabolismus   MeSH
• RNA interference MeSH
• RNA mitochondriální MeSH
• RNA genetika   MeSH
• Saccharomyces cerevisiae genetika   MeSH
• Trypanosoma brucei brucei genetika   MeSH
• viabilita buněk genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• gBP21 protein, Trypanosoma brucei MeSH Prohlížeč
• mitochondriální proteiny MeSH
• proteiny vázající RNA MeSH
• protozoální proteiny MeSH
• RNA mitochondriální MeSH
• RNA MeSH