Reading out the ubiquitin code during mitosis
UBASH3B is a critical factor for recruitment of Aurora B to mitotic microtubules, thereby controlling the speed and accuracy of chromosome segregation during human cell division.
Jan. 11, 2016
Cell division, known as mitotic division, is essential for the development of multicellular organisms from a single cell. Dysregulation of this process may contribute to the development of human cancers. Ubiquitin is a small protein that is conserved in eucaryotic cells. Ubiquitylation is a process in which one or more ubiquitin molecules are attached to target proteins. Ubiquitylation is a very versatile modification that can trigger degradation of the target protein or alternatively regulate its function. The plethora of different ubiquitin tags create a so called ubiquitin code. However, it remained unexplored how this code is read out during mitosis in human cells.
In a study published on January 11, 2016 in the journal Developmental Cell, the team of Izabela SUMARA at IGBMC demonstrated how the attachment of ubiquitin is decoded during mitosis. The team identified an ubiquitin-binding protein (ubiquitin receptor), named UBASH3B. This one interacts with ubiquitylated Aurora B, which is one of the main kinases regulating chromosome segregation during mitosis. Through this interaction, UBASH3B controls subcellular localization but not the protein levels of Aurora B. UBASH3B is a critical factor for recruitment of Aurora B to mitotic microtubules, thereby controlling the speed and accuracy of chromosome segregation during human cell division. This study could explain how misregulation of UBASH3B contributes to development of various human cancers.