The centrosome is the primary microtubule-organizing center of eukaryotic cells. In flagellate cells, the basal apparatus represents the functional equivalent of the mammalian centrosome. It anchors the flagella inside the cell and consists of the basal bodies (equivalent to centrioles) and associated cytoskeletal elements. Over the last 30 years our laboratory has contributed to the structural and functional analysis of the algal basal apparatus, starting with the discovery of the first centrosomal protein identified in a eukaryote, i.e. centrin (49*). Several additional centrosomal proteins were also first identified in algal flagellates, highlighting the importance of model systems such as Chlamydomonas reinhardtii and Spermatozopsis similis in cytoskeleton research.
Our current projects aim to identify, localize, and functionally characterize all structural proteins comprising the basal bodies using C. reinhardtii as a model system. Toward this end we have identified, using a proteome approach, about 50 core proteins in the basal bodies, many of them novel. Through a bioinformatics approach mammalian homologues are being identified. Defects in centrosomal/centriolar/basal body proteins are linked to important human diseases. Localization and functional analysis of the novel basal body proteins could thus help to understand the molecular basis for some of these diseases.

Contact: Kerstin Brachhold

*Number refers to the list of publications of Michael Melkonian

A self-guided “tour” through the basal apparatus of Spermatozopsis similis has been prepared for this site by Stefan Geimer (link)