Showing papers by "Kathleen L. Gould published in 2008"
TL;DR: In this article, the Mad3 and Mad2 spindle checkpoint proteins interact stably with the APC/C in mitosis, and the N-terminal KEN box of Mad3 was found to be a critical mediator of mitotic checkpoint inhibition.
102 citations
TL;DR: The evidence indicates that Clp1/Flp1 must interact with the Mid1 scaffold to ensure the fidelity of Schizosaccharomyces pombe cytokinesis, including dephosphorylation of the essential CR component Cdc15, reductions in CR protein mobility, and CR resistance to mild perturbation.
Abstract: Cdc14 phosphatases antagonize cyclin-dependent kinase–directed phosphorylation events and are involved in several facets of cell cycle control. We investigate the role of the fission yeast Cdc14 homologue Clp1/Flp1 in cytokinesis. We find that Clp1/Flp1 is tethered at the contractile ring (CR) through its association with anillin-related Mid1. Fluorescent recovery after photobleaching analyses indicate that Mid1, unlike other tested CR components, is anchored at the cell midzone, and this physical property is likely to account for its scaffolding role. By generating a mutation in mid1 that selectively disrupts Clp1/Flp1 tethering, we reveal the specific functional consequences of Clp1/Flp1 activity at the CR, including dephosphorylation of the essential CR component Cdc15, reductions in CR protein mobility, and CR resistance to mild perturbation. Our evidence indicates that Clp1/Flp1 must interact with the Mid1 scaffold to ensure the fidelity of Schizosaccharomyces pombe cytokinesis.
101 citations
TL;DR: It is shown that the most downstream SIN component, the Ndr-family kinase Sid2, maintains Clp1 in the cytoplasm in late mitosis by phosphorylating Clp 1 directly and thereby creating binding sites for the 14-3-3 protein Rad24.
78 citations
TL;DR: It is demonstrated that the SIN acts downstream from the Plo1 kinase to control a final step in contractile ring assembly, which may help bridge two existing models of cytokinetic ring formation.
Abstract: The septation initiation network (SIN) regulates the timing of septum formation in Schizosaccharomyces pombe. However, whether and how the SIN functions in contractile ring formation has remained unclear. In this issue of Genes & Development, Hachet and Simanis (pp. 3205-3216) demonstrate that the SIN acts downstream from the Plol kinase to control a final step in contractile ring assembly. Furthermore, their careful analysis of contractile ring formation may help bridge two existing models of cytokinetic ring formation.
61 citations
TL;DR: The elucidated roles of Cdc14 phosphatases in cytokinesis are reviewed and the current outstanding questions regarding their function in this process are reviewed.
Abstract: The periodicity of CDKs (cyclin-dependent kinases) regulates most cell cycle transitions including cytokinesis. High Cdk1 activity promotes cytoskeletal rearrangements necessary for cell division while at the same time ensuring that cytokinesis does not begin before the separation of sister chromatids during anaphase. The conserved Cdc14 (cell division cycle 14)-family of phosphatases reverses Cdk phosphorylation events and therefore Cdc14 phosphatases promote the process of cytokinesis. Here, we review the elucidated roles of Cdc14 phosphatases in cytokinesis and the current outstanding questions regarding their function in this process.
31 citations
01 Jan 2008
TL;DR: In the fission yeast, Schizosaccharomyces pombe, it is found that the Mad3 and Mad2 spindle checkpoint proteins interact stably with the APC/C in mitosis, and it is demonstrated that this Mad3 KEN box is a critical mediator of Cdc20-APc/C inhibition, without which neither Mad3 nor Mad2 can associate with theAPS or inhibit anaphase onset.
Abstract: Mitotic progression is driven by proteolytic destruction ofsecurin and cyclins. These proteins are labeled for destructionby an ubiquitin-protein isopeptide ligase (E3) known as theanaphase-promoting complex or cyclosome (APC/C). TheAPC/Crequiresactivators(Cdc20orCdh1)toefficientlyrecog-nize its substrates, which are specified by destruction (D box)and/or KEN box signals. The spindle assembly checkpointresponds to unattached kinetochores and to kinetochores lack-ing tension, both of which reflect incomplete biorientation ofchromosomes,bydelayingtheonsetofanaphase.Itdoesthisbyinhibiting Cdc20-APC/C. Certain checkpoint proteins interactdirectly with Cdc20, but it remains unclear how the checkpointacts to efficiently inhibit Cdc20-APC/C activity. In the fissionyeast,
13 citations