Abstract

Trypanosoma brucei, Trypanosoma cruzi and Leishmania species are protozoan parasites that cause Human African Trypanosomiasis, Chagas disease and Leishmaniasis, respectively. A common feature among these kinetoplast-containing parasites is the modification of cell shape during their life cycle. This involves important changes in the cytoskeleton and duplication and re-positioning of the single copy organelles. The cytoskeleton of these parasites is primarily based on a closely-knit helical microtubule array. Actin filaments have not been observed and no intermediate filament genes have been identified.

Due to this microtubule-based cytoskeleton T. brucei has a polarized cell biology, which has positive and negative morphological aspects to it. Positive aspects are that it is very stable and probably easily and rapidly modified for differentiation but on the other hand there is little room for endo and exocytosis. The array is only perforated at one point by a unique structure in the posterior of the cell called the flagellar pocket (FP) from which the flagellum emerges. Not surprisingly, the FP is also the exclusive region for endo- and exocytic activity. The FP has a unique ring-shaped cytoskeleton at its origin called the flagellar pocket collar (FPC), which is also attached to the flagellum at the site where the flagellum exits the cell. The only known protein present at, and within, the FPC is the essential protein TbBILBO1- a ring forming and precious protein.

Using a yeast-two-hybrid (Y2H) screen with TbBILBO1 as bait, we obtained new data that allowed the laboratory to assemble a list of putative TbBILBO1 interacting protein partners and these are currently being characterized to identify function, form and location. In this presentation I will discuss some of the properties and current thinking of the role(s) and organization of the FPC , its main component protein TbBILBO1 and some of its binding partners.