scholarly journals SIN-like pathway kinases regulate the end of mitosis in the methylotrophic yeast Ogataea polymorpha

2021 ◽  
Author(s):  
Shen Jiangyan ◽  
Kaoru Takegawa ◽  
Gislene Pereira ◽  
Hiromi Maekawa
Keyword(s):  
Budding Yeast ◽  
Methylotrophic Yeast ◽  
Growth Conditions ◽  
Mitotic Exit ◽  
Signalling Pathway ◽  
Significant Delay ◽  
Yeast Saccharomyces Cerevisiae ◽  
Mitotic Exit Network ◽  
Septation Initiation Network ◽  
Ogataea Polymorpha

The Mitotic exit network (MEN) is a conserved signalling pathway essential for termination of mitosis in the budding yeast Saccharomyces cerevisiae. All MEN components are highly conserved in the methylotrophic budding yeast Ogataea polymorpha, except for Cdc15 kinase. Amongst O. polymorpha protein kinases that have some similarity to ScCdc15, only two had no other obvious homologues in S. cerevisiae and these were named OpHCD1 and OpHCD2 for homologue candidate of ScCdc15. A search in other yeast species revealed that OpHcd2 has an armadillo type fold in the C-terminal region as found in SpCdc7 kinases of the fission yeast Schizosaccharomyces pombe, which are homologues of ScCdc15; while OpHcd1 is homologous to SpSid1 kinase, a component of the Septation Initiation Network (SIN) of S. pombe not present in the MEN. Since the deletion of either OpHCD1 or OpHCD2 resulted in lethality under standard growth conditions, conditional mutants were constructed by introducing an ATP analog sensitive mutation. For OpHCD2, we constructed and used new genetic tools for O. polymorpha that combined the Tet promoter and the improved auxin-degron systems. Conditional mutants for OpHCD1 and OpHCD2 exhibited significant delay in late anaphase and defective cell separation, suggesting that both genes have roles in mitotic exit and cytokinesis. These results suggest a SIN-like signalling pathway regulates termination of mitosis in O. polymorpha and that the loss of Sid1/Hcd1 kinase in the MEN occurred relatively recently during the evolution of budding yeast.

scholarly journals The Differential Roles of Budding Yeast Tem1p, Cdc15p, and Bub2p Protein Dynamics in Mitotic Exit

2004 ◽  
Vol 15 (4) ◽  
pp. 1519-1532 ◽  
Author(s):  
Jeffrey N. Molk ◽  
Scott C. Schuyler ◽  
Jenny Y. Liu ◽  
James G. Evans ◽  
E. D. Salmon ◽  
...  
Keyword(s):  
Budding Yeast ◽  
Protein Localization ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Mitotic Exit ◽  
Yeast Saccharomyces Cerevisiae ◽  
Late Anaphase ◽  
Gfp Fluorescence ◽  
Mitotic Exit Network

In the budding yeast Saccharomyces cerevisiae the mitotic spindle must be positioned along the mother-bud axis to activate the mitotic exit network (MEN) in anaphase. To examine MEN proteins during mitotic exit, we imaged the MEN activators Tem1p and Cdc15p and the MEN regulator Bub2p in vivo. Quantitative live cell fluorescence microscopy demonstrated the spindle pole body that segregated into the daughter cell (dSPB) signaled mitotic exit upon penetration into the bud. Activation of mitotic exit was associated with an increased abundance of Tem1p-GFP and the localization of Cdc15p-GFP on the dSPB. In contrast, Bub2p-GFP fluorescence intensity decreased in mid-to-late anaphase on the dSPB. Therefore, MEN protein localization fluctuates to switch from Bub2p inhibition of mitotic exit to Cdc15p activation of mitotic exit. The mechanism that elevates Tem1p-GFP abundance in anaphase is specific to dSPB penetration into the bud and Dhc1p and Lte1p promote Tem1p-GFP localization. Finally, fluorescence recovery after photobleaching (FRAP) measurements revealed Tem1p-GFP is dynamic at the dSPB in late anaphase. These data suggest spindle pole penetration into the bud activates mitotic exit, resulting in Tem1p and Cdc15p persistence at the dSPB to initiate the MEN signal cascade.

scholarly journals Order of function of the budding-yeast mitotic exit-network proteins Tem1, Cdc15, Mob1, Dbf2, and Cdc5

2001 ◽  
Vol 11 (10) ◽  
pp. 784-788 ◽  
Author(s):  
Sarah E. Lee ◽  
Lisa M. Frenz ◽  
Nicholas J. Wells ◽  
Anthony L. Johnson ◽  
Leland H. Johnston
Keyword(s):  
Budding Yeast ◽  
Mitotic Exit ◽  
Mitotic Exit Network

scholarly journals BFA1 has multiple positive roles in directing late mitotic events in S. cerevisiae

2018 ◽  
Author(s):  
J Whalen ◽  
C Sniffen ◽  
S Gartland ◽  
M Vannini ◽  
A Seshan
Keyword(s):  
Budding Yeast ◽  
Spindle Pole Body ◽  
Biological Significance ◽  
Spindle Pole ◽  
Mitotic Exit ◽  
Genome Integrity ◽  
Mitotic Exit Network ◽  
M Phase ◽  
Regulation Of Cell Cycle ◽  
Spindle Position

ABSTRACTThe proper regulation of cell cycle transitions is paramount to the maintenance of cellular genome integrity. In budding yeast, the mitotic exit network (MEN) is a Ras-like signaling cascade that effects the transition from M phase to G1 during the cell division cycle in budding yeast. MEN activation is tightly regulated. It occurs during anaphase and is coupled to mitotic spindle position by the spindle position checkpoint (SPoC). Bfa1 is a key component of the SPoC and functions as part of a two-component GAP complex along with Bub2. The GAP activity of Bfa1-Bub2 keeps the MEN GTPase Tem1 inactive in cells with mispositioned spindles, thereby preventing inappropriate mitotic exit and preserving genome integrity. Interestingly, a GAP-independent role for Bfa1 in mitotic exit regulation has been previously identified. However the nature of this Bub2-independent role and its biological significance are not understood. Here we show that Bfa1 also activates the MEN by promoting the localization of Tem1 primarily to the daughter spindle pole body (dSPB). We demonstrate that the overexpression of BFA1 is lethal due to defects in Tem1 localization, which is required for its activity. In addition, our studies demonstrate a Tem1-independent role for Bfa1 in promoting proper cytokinesis. Cells lacking TEM1, in which the essential mitotic exit function is bypassed, exhibit cytokinesis defects. These defects are suppressed by the overexpression of BFA1. We conclude that Bfa1 functions to both inhibit and activate late mitotic events.

scholarly journals A Novel Hyperactive Nud1 Mitotic Exit Network Scaffold Causes Spindle Position Checkpoint Bypass in Budding Yeast

Cells ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 46
Author(s):  
Michael Vannini ◽  
Victoria R. Mingione ◽  
Ashleigh Meyer ◽  
Courtney Sniffen ◽  
Jenna Whalen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Budding Yeast ◽  
Signal Transduction Pathway ◽  
Spindle Pole ◽  
Mitotic Exit ◽  
Independent Manner ◽  
Spindle Pole Bodies ◽  
Mitotic Exit Network ◽  
Cell Cycle Transition ◽  
Spindle Position

Mitotic exit is a critical cell cycle transition that requires the careful coordination of nuclear positioning and cyclin B destruction in budding yeast for the maintenance of genome integrity. The mitotic exit network (MEN) is a Ras-like signal transduction pathway that promotes this process during anaphase. A crucial step in MEN activation occurs when the Dbf2-Mob1 protein kinase complex associates with the Nud1 scaffold protein at the yeast spindle pole bodies (SPBs; centrosome equivalents) and thereby becomes activated. This requires prior priming phosphorylation of Nud1 by Cdc15 at SPBs. Cdc15 activation, in turn, requires both the Tem1 GTPase and the Polo kinase Cdc5, but how Cdc15 associates with SPBs is not well understood. We have identified a hyperactive allele of NUD1, nud1-A308T, that recruits Cdc15 to SPBs in all stages of the cell cycle in a CDC5-independent manner. This allele leads to early recruitment of Dbf2-Mob1 during metaphase and requires known Cdc15 phospho-sites on Nud1. The presence of nud1-A308T leads to loss of coupling between nuclear position and mitotic exit in cells with mispositioned spindles. Our findings highlight the importance of scaffold regulation in signaling pathways to prevent improper activation.

scholarly journals Chromosome passenger complexes control anaphase duration and spindle elongation via a kinesin-5 brake

2011 ◽  
Vol 193 (2) ◽  
pp. 285-294 ◽  
Author(s):  
Daniel K. Rozelle ◽  
Scott D. Hansen ◽  
Kenneth B. Kaplan
Keyword(s):  
Chromosome Segregation ◽  
Budding Yeast ◽  
Mitotic Exit ◽  
Mitotic Exit Network ◽  
Spindle Midzone ◽  
Spindle Elongation ◽  
Spindle Stability

During mitosis, chromosome passenger complexes (CPCs) exhibit a well-conserved association with the anaphase spindle and have been implicated in spindle stability. However, their precise effect on the spindle is not clear. In this paper, we show, in budding yeast, that a CPC consisting of CBF3, Bir1, and Sli15, but not Ipl1, is required for normal spindle elongation. CPC mutants slow spindle elongation through the action of the bipolar kinesins Cin8 and Kip1. The same CPC mutants that slow spindle elongation also result in the enrichment of Cin8 and Kip1 at the spindle midzone. Together, these findings argue that CPCs function to organize the spindle midzone and potentially switch motors between force generators and molecular brakes. We also find that slowing spindle elongation delays the mitotic exit network (MEN)–dependent release of Cdc14, thus delaying spindle breakdown until a minimal spindle size is reached. We propose that these CPC- and MEN-dependent mechanisms are important for coordinating chromosome segregation with spindle breakdown and mitotic exit.

scholarly journals Targeted localization of Inn1, Cyk3 and Chs2 by the mitotic-exit network regulates cytokinesis in budding yeast

2010 ◽  
Vol 123 (11) ◽  
pp. 1851-1861 ◽  
Author(s):  
F. Meitinger ◽  
B. Petrova ◽  
I. M. Lombardi ◽  
D. T. Bertazzi ◽  
B. Hub ◽  
...  
Keyword(s):  
Budding Yeast ◽  
Mitotic Exit ◽  
Mitotic Exit Network

scholarly journals IBD2 Encodes a Novel Component of the Bub2p-Dependent Spindle Checkpoint in the Budding Yeast Saccharomyces cerevisiae

Genetics ◽  
2002 ◽  
Vol 161 (2) ◽  
pp. 595-609
Author(s):  
Hyung-Seo Hwang ◽  
Kiwon Song
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Budding Yeast ◽  
Essential Gene ◽  
Spindle Checkpoint ◽  
Mitotic Arrest ◽  
Mitotic Exit ◽  
Wild Type ◽  
Yeast Saccharomyces Cerevisiae ◽  
Checkpoint Pathway

Abstract During mitosis, genomic integrity is maintained by the proper coordination of mitotic events through the spindle checkpoint. The bifurcated spindle checkpoint blocks cell cycle progression at metaphase by monitoring unattached kinetochores and inhibits mitotic exit in response to the incorrect orientation of the mitotic spindle. Bfa1p is a spindle checkpoint regulator of budding yeast in the Bub2p checkpoint pathway for proper mitotic exit. We have isolated a novel Bfa1p interacting protein named Ibd2p in the budding yeast Saccharomyces cerevisiae. We found that IBD2 (Inhibition of Bud Division 2) is not an essential gene but its deletion mutant proceeded through the cell cycle in the presence of microtubule-destabilizing drugs, thereby inducing a sharp decrease in viability. In addition, overexpression of Mps1p caused partial mitotic arrest in ibd2Δ as well as in bub2Δ, suggesting that IBD2 encodes a novel component of the spindle checkpoint downstream of MPS1. Overexpression of Ibd2p induced mitotic arrest with increased levels of Clb2p in wild type and mad2Δ, but not in deletion mutants of BUB2 and BFA1. Pds1p was also stabilized by the overexpression of Ibd2p in wild-type cells. The mitotic arrest defects observed in ibd2Δ in the presence of nocodazole were restored by additional copies of BUB2, BFA1, and CDC5, whereas an extra copy of IBD2 could not rescue the mitotic arrest defects of bub2Δ and bfa1Δ. The mitotic arrest defects of ibd2Δ were not recovered by MAD2, or vice versa. Analysis of the double mutant combinations ibd2Δmad2Δ, ibd2Δbub2Δ, and ibd2Δdyn1Δ showed that IBD2 belongs to the BUB2 epistasis group. Taken together, these data demonstrate that IBD2 encodes a novel component of the BUB2-dependent spindle checkpoint pathway that functions upstream of BUB2 and BFA1.

scholarly journals Budding yeast PAK kinases regulate mitotic exit by two different mechanisms

2003 ◽  
Vol 160 (6) ◽  
pp. 857-874 ◽  
Author(s):  
Elena Chiroli ◽  
Roberta Fraschini ◽  
Alessia Beretta ◽  
Mariagrazia Tonelli ◽  
Giovanna Lucchini ◽  
...  
Keyword(s):  
Cell Cycle Progression ◽  
Budding Yeast ◽  
Mitotic Exit ◽  
Dominant Negative ◽  
Anaphase Promoting Complex ◽  
Gene Encoding ◽  
Cycle Progression ◽  
Mitotic Exit Network ◽  
P21 Activated Kinase

We report the characterization of the dominant-negative CLA4t allele of the budding yeast CLA4 gene, encoding a member of the p21-activated kinase (PAK) family of protein kinases, which, together with its homologue STE20, plays an essential role in promoting budding and cytokinesis. Overproduction of the Cla4t protein likely inhibits both endogenous Cla4 and Ste20 and causes a delay in the onset of anaphase that correlates with inactivation of Cdc20/anaphase-promoting complex (APC)–dependent proteolysis of both the cyclinB Clb2 and securin. Although the precise mechanism of APC inhibition by Cla4t remains to be elucidated, our results suggest that Cla4 and Ste20 may regulate the first wave of cyclinB proteolysis mediated by Cdc20/APC, which has been shown to be crucial for activation of the mitotic exit network (MEN). We show that the Cdk1-inhibitory kinase Swe1 is required for the Cla4t-dependent delay in cell cycle progression, suggesting that it might be required to prevent full Cdc20/APC and MEN activation. In addition, inhibition of PAK kinases by Cla4t prevents mitotic exit also by a Swe1-independent mechanism impinging directly on the MEN activator Tem1.

scholarly journals The Nucleolar Net1/Cfi1-related Protein Dnt1 Antagonizes the Septation Initiation Network in Fission Yeast

2007 ◽  
Vol 18 (8) ◽  
pp. 2924-2934 ◽  
Author(s):  
Quan-Wen Jin ◽  
Samriddha Ray ◽  
Sung Hugh Choi ◽  
Dannel McCollum
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Sequence Homology ◽  
Mitotic Exit ◽  
Related Protein ◽  
Rdna Transcription ◽  
Minichromosome Maintenance ◽  
Nucleolar Proteins ◽  
Mitotic Exit Network ◽  
Septation Initiation Network

The septation initiation network (SIN) and mitotic exit network (MEN) signaling pathways regulate cytokinesis and mitotic exit in the yeasts Schizosaccharomyces pombe, and Saccharomyces cerevisiae, respectively. One function of these pathways is to keep the Cdc14-family phosphatase, called Clp1 in S. pombe, from being sequestered and inhibited in the nucleolus. In S. pombe, the SIN and Clp1 act as part of a cytokinesis checkpoint that allows cells to cope with cytokinesis defects. The SIN promotes checkpoint function by 1) keeping Clp1 out of the nucleolus, 2) maintaining the cytokinetic apparatus, and 3) halting the cell cycle until cytokinesis is completed. In a screen for suppressors of the SIN mutant cytokinesis checkpoint defect, we identified a novel nucleolar protein called Dnt1 and other nucleolar proteins, including Rrn5 and Nuc1, which are known to be required for rDNA transcription. Dnt1 shows sequence homology to Net1/Cfi1, which encodes the nucleolar inhibitor of Cdc14 in budding yeast. Like Net1/Cfi1, Dnt1 is required for rDNA silencing and minichromosome maintenance, and both Dnt1 and Net1/Cfi1 negatively regulate the homologous SIN and MEN pathways. Unlike Net1/Cfi1, which regulates the MEN through the Cdc14 phosphatase, Dnt1 can inhibit SIN signaling independently of Clp1, suggesting a novel connection between the nucleolus and the SIN pathway.

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