scholarly journals Requirement of the Dynein-adaptor Spindly for mitotic and post-mitotic functions in Drosophila

2017 ◽  
Author(s):  
Giuliana D. Clemente ◽  
Matthew R. Hannaford ◽  
Jens Januschke ◽  
Eric R. Griffis ◽  
Hans-Arno J. Muller
Keyword(s):  
Germ Line ◽  
Mitotic Checkpoint ◽  
Checkpoint Protein ◽  
C Elegans ◽  
Protein Levels ◽  
Egg Morphology ◽  
Female Germ Line ◽  
And Function ◽  
Mitotic Checkpoint Protein ◽  
Dynactin Complex

AbstractSpindly is a mitotic checkpoint protein originally identified as a specific regulator of Dynein activity at the kinetochore. In metaphase, Spindly recruits the Dynein/Dynactin complex, promoting the establishment of stable kinetochore-microtubule interactions and progression into anaphase. While details of Spindly function in mitosis have been worked out in cultured human cells and in the C. elegans zygote, the function of Spindly within the context of an organism has not yet been addressed. Here we present loss- and gain-of-function studies of Spindly in Drosophila. We investigated the requirements of distinct protein domains for the localisation and function of Spindly. We find that knock-down of Spindly results in a range of mitotic defects in the female germ line and during cleavage divisions in embryogenesis. Overexpression of Spindly in the female germ line is embryonic lethal and results in altered egg morphology. To determine whether Spindly plays a role in post-mitotic cells we altered Spindly protein levels in migrating cells and found that ovarian border cell migration is sensitive to the levels of Spindly protein. Our study uncovers novel functions of the mitotic checkpoint protein Spindly in Drosophila.

scholarly journals A novel role of farnesylation in targeting a mitotic checkpoint protein, human Spindly, to kinetochores

2015 ◽  
Vol 208 (7) ◽  
pp. 881-896 ◽  
Author(s):  
Devinderjit K. Moudgil ◽  
Nathan Westcott ◽  
Jakub K. Famulski ◽  
Kinjal Patel ◽  
Dawn Macdonald ◽  
...  
Keyword(s):  
Mitotic Checkpoint ◽  
Cysteine Residue ◽  
Farnesyl Transferase ◽  
Checkpoint Protein ◽  
Protein Protein Interaction ◽  
Domain Mapping ◽  
Mitotic Checkpoint Protein ◽  
Dynactin Complex

Kinetochore (KT) localization of mitotic checkpoint proteins is essential for their function during mitosis. hSpindly KT localization is dependent on the RZZ complex and hSpindly recruits the dynein–dynactin complex to KTs during mitosis, but the mechanism of hSpindly KT recruitment is unknown. Through domain-mapping studies we characterized the KT localization domain of hSpindly and discovered it undergoes farnesylation at the C-terminal cysteine residue. The N-terminal 293 residues of hSpindly are dispensable for its KT localization. Inhibition of farnesylation using a farnesyl transferase inhibitor (FTI) abrogated hSpindly KT localization without affecting RZZ complex, CENP-E, and CENP-F KT localization. We showed that hSpindly is farnesylated in vivo and farnesylation is essential for its interaction with the RZZ complex and hence KT localization. FTI treatment and hSpindly knockdown displayed the same mitotic phenotypes, indicating that hSpindly is a key FTI target in mitosis. Our data show a novel role of lipidation in targeting a checkpoint protein to KTs through protein–protein interaction.

scholarly journals Bub1 mediates cell death in response to chromosome missegregation and acts to suppress spontaneous tumorigenesis

2007 ◽  
Vol 179 (2) ◽  
pp. 255-267 ◽  
Author(s):  
Karthik Jeganathan ◽  
Liviu Malureanu ◽  
Darren J. Baker ◽  
Susan C. Abraham ◽  
Jan M. van Deursen
Keyword(s):  
Cell Death ◽  
Chromosome Segregation ◽  
Physiological Role ◽  
Mitotic Checkpoint ◽  
Critical Threshold ◽  
Wild Type ◽  
Checkpoint Protein ◽  
Chromosome Missegregation ◽  
Mitotic Checkpoint Protein

The physiological role of the mitotic checkpoint protein Bub1 is unknown. To study this role, we generated a series of mutant mice with a gradient of reduced Bub1 expression using wild-type, hypomorphic, and knockout alleles. Bub1 hypomorphic mice are viable, fertile, and overtly normal despite weakened mitotic checkpoint activity and high percentages of aneuploid cells. Bub1 haploinsufficient mice, which have a milder reduction in Bub1 protein than Bub1 hypomorphic mice, also exhibit reduced checkpoint activity and increased aneuploidy, but to a lesser extent. Although cells from Bub1 hypomorphic and haploinsufficient mice have similar rates of chromosome missegregation, cell death after an aberrant separation decreases dramatically with declining Bub1 levels. Importantly, Bub1 hypomorphic mice are highly susceptible to spontaneous tumors, whereas Bub1 haploinsufficient mice are not. These findings demonstrate that loss of Bub1 below a critical threshold drives spontaneous tumorigenesis and suggest that in addition to ensuring proper chromosome segregation, Bub1 is important for mediating cell death when chromosomes missegregate.

scholarly journals The Vertebrate Mitotic Checkpoint Protein BUBR1 Is an Unusual Pseudokinase

2012 ◽  
Vol 22 (6) ◽  
pp. 1321-1329 ◽  
Author(s):  
Saskia J.E. Suijkerbuijk ◽  
Teunis J.P. van Dam ◽  
G. Elif Karagöz ◽  
Eleonore von Castelmur ◽  
Nina C. Hubner ◽  
...  
Keyword(s):  
Mitotic Checkpoint ◽  
Checkpoint Protein ◽  
Mitotic Checkpoint Protein
Sign in / Sign up

Export Citation Format

Share Document