Centrin4 coordinates cell and nuclear division inT. brucei

Abstract

Centrins are Ca2+-binding proteins that have been implicated in a number of biological processes, including organelle duplication, mRNA export, DNA repair and signal transduction. In the protozoan parasite Trypanosoma brucei we have previously described TbCentrin2, which is present on a bi-lobed structure, and involved in the duplication and segregation of the Golgi complex. Recently, another centrin, TbCentrin4, was also found at the bi-lobe and has been implicated in organelle segregation and cytokinesis. We now show that cytokinesis is not inhibited, but that a dysregulation of nuclear and cell division leads to the production of zoids – daughter siblings that contain all organelles except the nucleus. Our results, therefore, suggest that TbCentrin4 is involved in processes that coordinate karyokinesis and cytokinesis.

A coiled-coil- and C2-domain-containing protein is required for FAZ assembly and cell morphology in Trypanosoma brucei

“…2D) (Sevova and Bangs, 2009), where the bi-lobed structure was previously mapped (He et al, 2005;Shi et al, 2008). This result was therefore consistent with the partial overlap between the bi-lobe and the FAZ previously observed by light microscopy (supplementary material Fig.…”

“…S2D-F). FAZ1-labeled FAZ was previously shown to partially overlap with the bi-lobed structure marked with Centrin4, a small EF-hand-containing protein found on both the basal bodies and the bi-lobe in T. brucei (Shi et al, 2008). Similar overlap with the bi-lobe was also observed for Ty-CC2D, with the posterior tip of CC2D-labeling overlapping with the Centrin4-labeled bi-lobe (supplementary material Fig.…”

“…Inhibited flagellum formation in intraflagellar transport mutants results in truncated FAZ (Absalon et al, 2007;Kohl et al, 2003). Furthermore, our previous work suggests a possible link between the FAZ filament and the Golgiadjacent bi-lobed structure, which plays a crucial role in organelle biogenesis and cell division (Morriswood et al, 2009;Shi et al, 2008;Zhou et al, 2010). The centrally located bi-lobe overlaps with the posterior tip of the FAZ and duplication of the bi-lobe is immediately followed by formation of a new FAZ.…”

Structure of the TbBILBO1 Protein N-terminal Domain from Trypanosoma brucei Reveals an Essential Requirement for a Conserved Surface Patch

“…To analyze whether the detached flagella were proximally associated with a basal body, the cells were co-labeled with TbCentrin4. TbCentrin4 localizes to both the basal body and a cytoskeletal structure called the bilobe (21,22). In duplicating cells overexpressing Ty1-TbBILBO1-FL, TbCentrin4-labeled basal bodies were observed at the base of both old and new flagella (Fig.…”

A Novel Basal Body Protein That Is a Polo-like Kinase Substrate Is Required for Basal Body Segregation and Flagellum Adhesion in Trypanosoma brucei

“…A number of proteins have been localized to the basal body in T. brucei, but only a few of them are localized to both the probasal body and the mature basal body, which includes TbCentrin2 (17,36), TbCentrin4 (38), , and an unknown protein that is recognized by a monoclonal antibody BBA4 (39). Centrins and SAS-6 are evolutionarily conserved components of the centriole/basal body, and are present in all of the eukaryotic organisms investigated so far (40,41).…”