Faculty Opinions recommendation of Sfi1p has conserved centrin-binding sites and an essential function in budding yeast spindle pole body duplication.

2003 ◽  
Author(s):  
Michel Bornens
Keyword(s):  
Binding Sites ◽  
Budding Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body ◽  
Essential Function

scholarly journals Sfi1p has conserved centrin-binding sites and an essential function in budding yeast spindle pole body duplication

2003 ◽  
Vol 162 (7) ◽  
pp. 1211-1221 ◽  
Author(s):  
John V. Kilmartin
Keyword(s):  
Single Molecule ◽  
Protein A ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Binding Motif ◽  
Temperature Sensitive ◽  
Pole Body ◽  
Human Proteins ◽  
Z Domain ◽  
Essential Function

Centrins are calmodulin-like proteins present in microtubule-organizing centers. The Saccharomyces cerevisiae centrin, Cdc31p, was functionally tagged with a single Z domain of protein A, and used in pull-down experiments to isolate Cdc31p-binding proteins. One of these, Sfi1p, localizes to the half-bridge of the spindle pole body (SPB), where Cdc31p is also localized. Temperature-sensitive mutants in SFI1 show a defect in SPB duplication and genetic interactions with cdc31-1. Sfi1p contains multiple internal repeats that are also present in a Schizosaccharomyces pombe protein, which also localizes to the SPB, and in several human proteins, one of which localizes close to the centriole region. Cdc31p binds directly to individual Sfi1 repeats in a 1:1 ratio, so a single molecule of Sfi1p binds multiple molecules of Cdc31p. The centrosomal human protein containing Sfi1 repeats also binds centrin in the repeat region, showing that this centrin-binding motif is conserved.

scholarly journals N-terminal regions of Mps1 kinase determine functional bifurcation

2010 ◽  
Vol 189 (1) ◽  
pp. 41-56 ◽  
Author(s):  
Yasuhiro Araki ◽  
Linda Gombos ◽  
Suellen P.S. Migueleti ◽  
Lavanya Sivashanmugam ◽  
Claude Antony ◽  
...  
Keyword(s):  
Nuclear Envelope ◽  
Chemical Biology ◽  
Molecular Level ◽  
Budding Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Deletion Analysis ◽  
Checkpoint Activation ◽  
Pole Body ◽  
N Terminus

Mps1 is a conserved kinase that in budding yeast functions in duplication of the spindle pole body (SPB), spindle checkpoint activation, and kinetochore biorientation. The identity of Mps1 targets and the subdomains that convey specificity remain largely unexplored. Using a novel combination of systematic deletion analysis and chemical biology, we identified two regions within the N terminus of Mps1 that are essential for either SPB duplication or kinetochore biorientation. Suppression analysis of the MPS1 mutants defective in SPB duplication and biochemical enrichment of Mps1 identified the essential SPB components Spc29 and the yeast centrin Cdc31 as Mps1 targets in SPB duplication. Our data suggest that phosphorylation of Spc29 by Mps1 in G1/S recruits the Mps2–Bbp1 complex to the newly formed SPB to facilitate its insertion into the nuclear envelope. Mps1 phosphorylation of Cdc31 at the conserved T110 residue controls substrate binding to Kar1 protein. These findings explain the multiple SPB duplication defects of mps1 mutants on a molecular level.

scholarly journals Phosphorylation and spindle pole body localization of the Cdc15p mitotic regulatory protein kinase in budding yeast

2000 ◽  
Vol 10 (6) ◽  
pp. 329-332 ◽  
Author(s):  
Shuichan Xu ◽  
Han-Kuei Huang ◽  
Peter Kaiser ◽  
Martin Latterich ◽  
Tony Hunter
Keyword(s):  
Protein Kinase ◽  
Budding Yeast ◽  
Regulatory Protein ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body

scholarly journals Regulation of spindle pole body assembly and cytokinesis by the centrin-binding protein Sfi1 in fission yeast

2014 ◽  
Vol 25 (18) ◽  
pp. 2735-2749 ◽  
Author(s):  
I-Ju Lee ◽  
Ning Wang ◽  
Wen Hu ◽  
Kersey Schott ◽  
Jürg Bähler ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Fission Yeast ◽  
Budding Yeast ◽  
Binding Protein ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Centrosome Duplication ◽  
Pole Body ◽  
The Individual

Centrosomes play critical roles in the cell division cycle and ciliogenesis. Sfi1 is a centrin-binding protein conserved from yeast to humans. Budding yeast Sfi1 is essential for the initiation of spindle pole body (SPB; yeast centrosome) duplication. However, the recruitment and partitioning of Sfi1 to centrosomal structures have never been fully investigated in any organism, and the presumed importance of the conserved tryptophans in the internal repeats of Sfi1 remains untested. Here we report that in fission yeast, instead of doubling abruptly at the initiation of SPB duplication and remaining at a constant level thereafter, Sfi1 is gradually recruited to SPBs throughout the cell cycle. Like an sfi1Δ mutant, a Trp-to-Arg mutant (sfi1-M46) forms monopolar spindles and exhibits mitosis and cytokinesis defects. Sfi1-M46 protein associates preferentially with one of the two daughter SPBs during mitosis, resulting in a failure of new SPB assembly in the SPB receiving insufficient Sfi1. Although all five conserved tryptophans tested are involved in Sfi1 partitioning, the importance of the individual repeats in Sfi1 differs. In summary, our results reveal a link between the conserved tryptophans and Sfi1 partitioning and suggest a revision of the model for SPB assembly.

scholarly journals The half-bridge component Kar1 promotes centrosome separation and duplication during budding yeast meiosis

2018 ◽  
Vol 29 (15) ◽  
pp. 1798-1810
Author(s):  
Meenakshi Agarwal ◽  
Hui Jin ◽  
Melainia McClain ◽  
Jinbo Fan ◽  
Bailey A. Koch ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Budding Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Pole Body ◽  
Centrosome Separation ◽  
Chromatid Segregation ◽  
Yeast Meiosis ◽  
Unique Mechanism

The budding yeast centrosome, often called the spindle pole body (SPB), nucleates microtubules for chromosome segregation during cell division. An appendage, called the half bridge, attaches to one side of the SPB and regulates SPB duplication and separation. Like DNA, the SPB is duplicated only once per cell cycle. During meiosis, however, after one round of DNA replication, two rounds of SPB duplication and separation are coupled with homologue segregation in meiosis I and sister-chromatid segregation in meiosis II. How SPB duplication and separation are regulated during meiosis remains to be elucidated, and whether regulation in meiosis differs from that in mitosis is unclear. Here we show that overproduction of the half-bridge component Kar1 leads to premature SPB separation during meiosis. Furthermore, excessive Kar1 induces SPB overduplication to form supernumerary SPBs, leading to chromosome missegregation and erroneous ascospore formation. Kar1-­mediated SPB duplication bypasses the requirement of dephosphorylation of Sfi1, another half-bridge component previously identified as a licensing factor. Our results therefore reveal an unexpected role of Kar1 in licensing meiotic SPB duplication and suggest a unique mechanism of SPB regulation during budding yeast meiosis.

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