scholarly journals The fission yeast septation initiation network (SIN) kinase, Sid2, is required for SIN asymmetry and regulates the SIN scaffold, Cdc11

2012 ◽  
Vol 23 (9) ◽  
pp. 1636-1645 ◽  
Author(s):  
Anna Feoktistova ◽  
Jennifer Morrell-Falvey ◽  
Jun-Song Chen ◽  
N. Sadananda Singh ◽  
Mohan K. Balasubramanian ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Asymmetric Distribution ◽  
Kinase Cascade ◽  
Septation Initiation Network ◽  
Ring Constriction ◽  
Signaling Components ◽  
Protein Kinase Cascade

The Schizosaccharomyces pombe septation initiation network (SIN) is an Spg1-GTPase–mediated protein kinase cascade that triggers actomyosin ring constriction, septation, and cell division. The SIN is assembled at the spindle pole body (SPB) on the scaffold proteins Cdc11 and Sid4, with Cdc11 binding directly to SIN signaling components. Proficient SIN activity requires the asymmetric distribution of its signaling components to one of the two SPBs during anaphase, and Cdc11 hyperphosphorylation correlates with proficient SIN activity. In this paper, we show that the last protein kinase in the signaling cascade, Sid2, feeds back to phosphorylate Cdc11 during mitosis. The characterization of Cdc11 phosphomutants provides evidence that Sid2-mediated Cdc11 phosphorylation promotes the association of the SIN kinase, Cdc7, with the SPB and maximum SIN signaling during anaphase. We also show that Sid2 is crucial for the establishment of SIN asymmetry, indicating a positive-feedback loop is an important element of the SIN.

scholarly journals Cdk1 promotes cytokinesis in fission yeast through activation of the septation initiation network

2014 ◽  
Vol 25 (15) ◽  
pp. 2250-2259 ◽  
Author(s):  
Nicole Rachfall ◽  
Alyssa E. Johnson ◽  
Sapna Mehta ◽  
Jun-Song Chen ◽  
Kathleen L. Gould
Keyword(s):  
Cell Cycle ◽  
Spindle Pole Body ◽  
Complete Removal ◽  
Spindle Pole ◽  
Cyclin Dependent Kinase ◽  
Gtpase Activating Protein ◽  
Pole Body ◽  
Kinase Cascade ◽  
Septation Initiation Network ◽  
Cycle Dependent

In Schizosaccharomyces pombe, late mitotic events are coordinated with cytokinesis by the septation initiation network (SIN), an essential spindle pole body (SPB)–associated kinase cascade, which controls the formation, maintenance, and constriction of the cytokinetic ring. It is not fully understood how SIN initiation is temporally regulated, but it depends on the activation of the GTPase Spg1, which is inhibited during interphase by the essential bipartite GTPase-activating protein Byr4-Cdc16. Cells are particularly sensitive to the modulation of Byr4, which undergoes cell cycle–dependent phosphorylation presumed to regulate its function. Polo-like kinase, which promotes SIN activation, is partially responsible for Byr4 phosphorylation. Here we show that Byr4 is also controlled by cyclin-dependent kinase (Cdk1)–mediated phosphorylation. A Cdk1 nonphosphorylatable Byr4 phosphomutant displays severe cell division defects, including the formation of elongated, multinucleate cells, failure to maintain the cytokinetic ring, and compromised SPB association of the SIN kinase Cdc7. Our analyses show that Cdk1-mediated phosphoregulation of Byr4 facilitates complete removal of Byr4 from metaphase SPBs in concert with Plo1, revealing an unexpected role for Cdk1 in promoting cytokinesis through activation of the SIN pathway.

scholarly journals Identification and characterization of novel components of a Ca2+/calmodulin-dependent protein kinase cascade in HeLa cells

FEBS Letters ◽  
2003 ◽  
Vol 550 (1-3) ◽  
pp. 57-63 ◽  
Author(s):  
Yumi Ishikawa ◽  
Hiroshi Tokumitsu ◽  
Hiroyuki Inuzuka ◽  
Maki Murata-Hori ◽  
Hiroshi Hosoya ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Hela Cells ◽  
Dependent Protein Kinase ◽  
Kinase Cascade ◽  
Dependent Protein ◽  
Identification And Characterization ◽  
Protein Kinase Cascade

scholarly journals Roles of Pdk1p, a Fission Yeast Protein Related to Phosphoinositide-dependent Protein Kinase, in the Regulation of Mitosis and Cytokinesis

2005 ◽  
Vol 16 (7) ◽  
pp. 3162-3175 ◽  
Author(s):  
Andrea Bimbó ◽  
Jianhua Liu ◽  
Mohan K. Balasubramanian
Keyword(s):  
Protein Kinase ◽  
Fission Yeast ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Yeast Protein ◽  
Dependent Protein Kinase ◽  
Multiple Processes ◽  
Regulate Cell Growth ◽  
Septation Initiation Network ◽  
Dependent Protein

Proteins related to the phosphoinositide-dependent protein kinase family have been identified in the majority of eukaryotes. Although much is known about upstream mechanisms that regulate the PDK1-family of kinases in metazoans, how these kinases regulate cell growth and division remains unclear. Here, we characterize a fission yeast protein related to members of this family, which we have termed Pdk1p. Pdk1p localizes to the spindle pole body and the actomyosin ring in early mitotic cells. Cells deleted for pdk1 display multiple defects in mitosis and cytokinesis, all of which are exacerbated when the function of fission yeast polo kinase, Plo1p, is partially compromised. We conclude that Pdk1p functions in concert with Plo1p to regulate multiple processes such as the establishment of a bipolar mitotic spindle, transition to anaphase, placement of the actomyosin ring and proper execution of cytokinesis. We also present evidence that the effects of Pdk1p on cytokinesis are likely mediated via the fission yeast anillin-related protein, Mid1p, and the septation initiation network.

scholarly journals Characterization of a Ca2+/Calmodulin-dependent Protein Kinase Cascade

1995 ◽  
Vol 270 (33) ◽  
pp. 19320-19324 ◽  
Author(s):  
Hiroshi Tokumitsu ◽  
Hervé Enslen ◽  
Thomas R. Soderling
Keyword(s):  
Protein Kinase ◽  
Dependent Protein Kinase ◽  
Kinase Cascade ◽  
Dependent Protein ◽  
Protein Kinase Cascade

scholarly journals Ppc89 Links Multiple Proteins, Including the Septation Initiation Network, to the Core of the Fission Yeast Spindle-Pole Body

2006 ◽  
Vol 17 (9) ◽  
pp. 3793-3805 ◽  
Author(s):  
Joshua A. Rosenberg ◽  
Gregory C. Tomlin ◽  
W. Hayes McDonald ◽  
Brian E. Snydsman ◽  
Eric G. Muller ◽  
...  
Keyword(s):  
Chromosome Segregation ◽  
Spindle Pole Body ◽  
Spindle Pole ◽  
Uncharacterized Protein ◽  
Central Function ◽  
Pole Body ◽  
Organizing Center ◽  
Septation Initiation Network ◽  
Ring Constriction ◽  
Essential Function

The spindle-pole body (SPB), the yeast analog of the centrosome, serves as the major microtubule (MT) organizing center in the yeast cell. In addition to this central function, the SPB organizes and concentrates proteins required for proper coordination between the nuclear-division cycle and cytokinesis. For example, the Schizosaccharomyces pombe septation-initiation network (SIN), which is responsible for initiating actomyosin ring constriction and septation, is assembled at the SPB through its two scaffolding components, Sid4 and Cdc11. In an effort to identify novel SIN interactors, we purified Cdc11 and identified by mass spectrometry a previously uncharacterized protein associated with it, Ppc89. Ppc89 localizes constitutively to the SPB and interacts directly with Sid4. A fusion between the N-terminal 300 amino acids of Sid4 and a SPB targeting domain of Ppc89 supplies the essential function of Sid4 in anchoring the SIN. ppc89Δ cells are inviable and exhibit defects in SPB integrity, and hence in spindle formation, chromosome segregation, and SIN localization. Ppc89 overproduction is lethal, resulting primarily in a G2 arrest accompanied by massive enlargement of the SPB and increased SPB MT nucleation. These results suggest a fundamental role for Ppc89 in organization of the S. pombe SPB.

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