Consequences of microtubule posttranslational modifications on the physics of the parasite Trypanosoma brucei - Part II

• Applicants: Professor Dr. Klaus Ersfeld; Professor Dr. Matthias Weiss
• Subject Area: Biophysics ; Parasitology and Biology of Tropical Infectious Disease Pathogens ; Statistical Physics, Nonlinear Dynamics, Complex Systems, Soft and Fluid Matter, Biological Physics ; Cell Biology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 491707420

The objective of this project is a comprehensive characterisation of the role of microtubule post-translational modifications (PTMs) on the physical and cell biological properties of the human pathogenic parasite Trypanosoma brucei. The microtubule-based cytoskeleton is key of numerous aspects of the life cycle of T. brucei, including cell motility morphology and adaptations during life cycle differentiation. To date, little is known of how cytoskeletal dynamics is regulated and its impact on the physics of the parasite. In our project we characterise the roles of three sets of PTMs: polyglutamylation, (de)tyrosination, and acetylation. During the first funding period we have developed strains of the procyclic trypanosome form that are deficient for the enzymes catalysing these modifications. The strains were investigated using cell biological techniques in combination with quantitative motility assays. This enabled us to describe morphological alterations and to quantify important parameters of the cell's locomotion, such as the intermittently changing velocity and motion straightness. Based on this, we will add more detailed and complex analyses during the second funding period. In particular, mutant strains of bloodstream form trypanosomes will be created and investigated at an ultrastructural level in order to reveal subtle changes in cytoskeletal structures. Furthermore, for all mutant strains we will quantify the characteristic velocity of individual cells and the apparent stiffness of their cytoskeleton via video microscopy ('cell tracking') in various microfluidic environments that mimic the parasite's natural habitat, e.g. in tiny aqueous droplets and maze-like chambers with soft and/or mobile obstacles. Here, also the impact of an external flow will be investigated, which is expected to have a significant influence at least on bloodstream form trypanosomes. We expect this project, together with the results of the first funding period, to provide a comprehensive understanding on the specific impact of microtubule PTMs on the (bio)physics of T. brucei.

• DFG Programme: Priority Programmes
• Subproject of: SPP 2332: Physics of Parasitism