A Novel Basal Body Protein That Is a Polo-like Kinase Substrate Is Required for Basal Body Segregation and Flagellum Adhesion in Trypanosoma brucei.
The Polo-like kinase (PLK) in Trypanosoma brucei plays multiple roles in basal body segregation, flagellum attachment, and cytokinesis. However, the mechanistic role of TbPLK remains elusive, mainly because most of its substrates are not known. Here, we report a new substrate of TbPLK, SPBB1, and its essential roles in T. brucei. SPBB1 was identified through yeast two-hybrid screening with the kinase-dead TbPLK as the bait. It interacts with TbPLK in vitro and in vivo, and is phosphorylated by TbPLK in vitro. SPBB1 localizes to both the mature basal body and the probasal body throughout the cell cycle, and co-localizes with TbPLK at the basal body during early cell cycle stages. RNAi against SPBB1 in procyclic trypanosomes inhibited basal body segregation, disrupted the new flagellum attachment zone filament, detached the new flagellum, and caused defective cytokinesis. Moreover, RNAi of SPBB1 confined TbPLK at the basal body and the bilobe structure, resulting in constitutive phosphorylation of TbCentrin2 at the bilobe. Altogether, these results identified a basal body protein as a TbPLK substrate and its essential role in promoting basal body segregation and flagellum attachment zone filament assembly for flagellum adhesion and cytokinesis initiation.
From the Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, Texas 77030.
Huiqing
H
Hu
From the Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, Texas 77030.
Qing
Q
Zhou
From the Department of Microbiology and Molecular Genetics, University of Texas Medical School, Houston, Texas 77030 Ziyin.Li@uth.tmc.edu.
Ziyin
Z
Li
D064652:Basal Bodies / Q000378:metabolism*; D002448:Cell Adhesion; D002453:Cell Cycle; D018797:Cell Cycle Proteins / Q000378:metabolism*; D048749:Cytokinesis; D005407:Flagella / Q000378:metabolism*; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D021381:Protein Transport; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D014346:Trypanosoma brucei brucei / Q000166:cytology* / Q000378:metabolism*; D000097869:Polo-Like Kinase 1
D018797:Cell Cycle Proteins; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D015800:Protozoan Proteins; D000097869:Polo-Like Kinase 1
Polo-like kinase; Trypanosoma brucei; basal body; flagellum; flagellum attachment zone; gene silencing; molecular cell biology; parasite; parasitology