Identification of a novel chromosomal passenger complex and its unique localization during cytokinesis in Trypanosoma brucei.
Aurora B kinase is a key component of the chromosomal passenger complex (CPC), which regulates chromosome segregation and cytokinesis. An ortholog of Aurora B was characterized in Trypanosoma brucei (TbAUK1), but other conserved components of the complex have not been found. Here we identified four novel TbAUK1 associated proteins by tandem affinity purification and mass spectrometry. Among these four proteins, TbKIN-A and TbKIN-B are novel kinesin homologs, whereas TbCPC1 and TbCPC2 are hypothetical proteins without any sequence similarity to those known CPC components from yeasts and metazoans. RNAi-mediated silencing of each of the four genes led to loss of spindle assembly, chromosome segregation and cytokinesis. TbKIN-A localizes to the mitotic spindle and TbKIN-B to the spindle midzone during mitosis, whereas TbCPC1, TbCPC2 and TbAUK1 display the dynamic localization pattern of a CPC. After mitosis, the CPC disappears from the central spindle and re-localizes at a dorsal mid-point of the mother cell, where the anterior tip of the daughter cell is tethered, to start cell division toward the posterior end, indicating a most unusual CPC-initiated cytokinesis in a eukaryote.
Li
Ziyin
Z
Department of Pharmaceutical Chemistry, University of California San Francisco, San Francisco, California, United States of America.
Lee
Ju Huck
JH
Chu
Feixia
F
Burlingame
Alma L
AL
Günzl
Arthur
A
Wang
Ching C
CC
D000818:Animals; D002453:Cell Cycle; D002467:Cell Nucleus / Q000378:metabolism; D002846:Chromatography, Affinity; D002875:Chromosomes; D020868:Gene Silencing; D013058:Mass Spectrometry; D008938:Mitosis; D034622:RNA Interference; D008941:Spindle Apparatus; D014346:Trypanosoma brucei brucei / Q000235:genetics / Q000378:metabolism*