TAC102 is a novel component of the mitochondrial genome segregation machinery in trypanosomes

Trypanosomes show an intriguing organization of their mitochondrial DNA into a catenated network, the kinetoplast DNA (kDNA). While more than 30 proteins involved in kDNA replication have been described, only few components of kDNA segregation machinery are currently known. Electron microscopy studies identified a high-order structure, the tripartite attachment complex (TAC), linking the basal body of the flagellum via the mitochondrial membranes to the kDNA. Here we describe TAC102, a novel core component of the TAC, which is essential for proper kDNA segregation during cell division. Loss of TAC102 leads to mitochondrial genome missegregation but has no impact on proper organelle biogenesis and segregation. The protein is present throughout the cell cycle and is assembled into the newly developing TAC only after the pro-basal body has matured indicating a hierarchy in the assembly process. Furthermore, we provide evidence that the TAC is replicated de novo rather than using a semi-conservative mechanism. Lastly, we demonstrate that TAC102 lacks an N-terminal mitochondrial targeting sequence and requires sequences in the C-terminal part of the protein for its proper localization

An interplay between Centrin2 and Centrin4 on the bi-lobed structure in Trypanosoma brucei

10.1111/j.1365-2958.2012.07998.xMolecular Microbiology8361153-1161MOMI

Structure of Trypanosoma brucei flagellum accounts for its bihelical motion

Trypanosoma brucei is a parasitic protozoan that causes African sleeping sickness. It contains a flagellum required for locomotion and viability. In addition to a microtubular axoneme, the flagellum contains a crystalline paraflagellar rod (PFR) and connecting proteins. We show here, by cryoelectron tomography, the structure of the flagellum in three bending states. The PFR lattice in straight flagella repeats every 56 nm along the length of the axoneme, matching the spacing of the connecting proteins. During flagellar bending, the PFR crystallographic unit cell lengths remain constant while the interaxial angles vary, similar to a jackscrew. The axoneme drives the expansion and compression of the PFR lattice. We propose that the PFR modifies the in-plane axoneme motion to produce the characteristic trypanosome bihelical motility as captured by high-speed light microscope videography

Characterization, Deposition Mechanisms and Modeling of Metallic Glass Powders for Cold Spray

This chapter describes recent efforts to understand the effects that chemical and physical properties of metallic glass (MG) powder particles have on the synthesis of their cold-sprayed coatings. Understanding the mechanical response of MG is fundamental to evaluate the conditions at which their powder particles can be deposited by cold spray. The characteristics of the feedstock powders are evaluated and used to ascertain ideal cold spray parameters. This information is also used to model the deposition mechanism of metallic glasses in the cold spray process. FE analysis and simulation is used to identify the phenomena behind the formation of MG coatings (i.e., homogenous or inhomogeneous deformation). The model defined considers strain rate and temperature dependence of MGs under different conditions