scholarly journals Hsl1p, a Swe1p Inhibitor, Is Degraded via the Anaphase-Promoting Complex

2000 ◽  
Vol 20 (13) ◽  
pp. 4614-4625 ◽  
Author(s):  
Janet L. Burton ◽  
Mark J. Solomon
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
26S Proteasome ◽  
Dependent Manner ◽  
Cell Cycle Regulators ◽  
Anaphase Promoting Complex ◽  
Protein Substrates ◽  
Subsequent Degradation ◽  
Apc Mutation ◽  
Destruction Box

ABSTRACT Ubiquitination and subsequent degradation of critical cell cycle regulators is a key mechanism exploited by the cell to ensure an irreversible progression of cell cycle events. The anaphase-promoting complex (APC) is a ubiquitin ligase that targets proteins for degradation by the 26S proteasome. Here we identify the Hsl1p protein kinase as an APC substrate that interacts with Cdc20p and Cdh1p, proteins that mediate APC ubiquitination of protein substrates. Hsl1p is absent in G1, accumulates as cells begin to bud, and disappears in late mitosis. Hsl1p is stabilized by mutations inCDH1 and CDC23, both of which result in compromised APC activity. Unlike Hsl1p, Gin4p and Kcc4p, protein kinases that have sequence homology to Hsl1p, were stable in G1-arrested cells containing active APC. Mutation of a destruction box motif within Hsl1p (Hsl1pdb-mut) stabilized Hsl1p. Interestingly, this mutation also disrupted the Hsl1p-Cdc20p interaction and reduced the association between Hsl1p and Cdh1p in coimmunoprecipitation studies. These findings suggest that the destruction box motif is required for Cdc20p and, to a lesser extent, for Cdh1p to target Hsl1p to the APC for ubiquitination. Hsl1p has been previously shown to inhibit Swe1p, a protein kinase that negatively regulates the cyclin-dependent kinase Cdc28p, by promoting Swe1p degradation via SCFMet30 in a bud morphogenesis checkpoint. Results of the present work indicate that Hsl1p is degraded in an APC-dependent manner and suggest a link between the SCF (Skp1-cullin-F box) and APC-proteolytic systems that may help to coordinate the proper progression of cell cycle events.

scholarly journals APC/C Cdh1-mediated degradation of Cdh1 during meiosis in S. cerevisiae

2018 ◽  
Author(s):  
Denis Ostapenko ◽  
Mark J. Solomon
Keyword(s):  
Cell Cycle ◽  
Binding Sites ◽  
Mitotic Cell ◽  
Sporulation Medium ◽  
Cell Cycle Regulators ◽  
Anaphase Promoting Complex ◽  
Cell Cycles ◽  
Activator Proteins ◽  
Subsequent Degradation ◽  
Numerous Cell

ABSTRACTThe Anaphase-Promoting Complex/Cyclosome (APC/C) is a ubiquitin ligase that promotes the ubiquitination and subsequent degradation of numerous cell cycle regulators during mitosis and in G1. Proteins are recruited to the APC/C by activator proteins such as Cdh1. During the cell cycle, Cdh1 is subject to precise regulation so that substrates are not degraded prematurely. We have explored the regulation of Cdh1 during the developmental transition into meiosis and sporulation in the budding yeast S. cerevisiae. Transition to sporulation medium triggers the degradation of Cdh1. Degradation requires that cells be of the a/a mating type and be starved for glucose, but they do not actually need to enter into the meiotic program. Degradation requires an intact SNF1 protein kinase complex (orthologous to the mammalian AMPK nutritional sensor), which is activated by the absence of glucose. Cdh1 degradation is mediated by the APC/C itself in a ‘trans’ mechanism in which one molecule of Cdh1 recruits a second molecule of Cdh1 to the APC/C for ubiquitination. However, Cdh1-Cdh1 recognition does not depend on the degradation motifs or binding sites involved in the recognition of typical APC/C substrates. We hypothesize that Cdh1 degradation is necessary for the preservation of cell cycle regulators and chromosome cohesion proteins between the reductional and equational meiotic divisions, which occur without the intervening Gap or S phases found in mitotic cell cycles.

scholarly journals Visualizing the complex functions and mechanisms of the anaphase promoting complex/cyclosome (APC/C)

Open Biology ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. 170204 ◽  
Author(s):  
Claudio Alfieri ◽  
Suyang Zhang ◽  
David Barford
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Spindle Assembly Checkpoint ◽  
Dependent Manner ◽  
Cell Cycle Regulators ◽  
Anaphase Promoting Complex ◽  
Polyubiquitin Chains ◽  
A Cell ◽  
Specific Proteins ◽  
Cycle Dependent

The anaphase promoting complex or cyclosome (APC/C) is a large multi-subunit E3 ubiquitin ligase that orchestrates cell cycle progression by mediating the degradation of important cell cycle regulators. During the two decades since its discovery, much has been learnt concerning its role in recognizing and ubiquitinating specific proteins in a cell-cycle-dependent manner, the mechanisms governing substrate specificity, the catalytic process of assembling polyubiquitin chains on its target proteins, and its regulation by phosphorylation and the spindle assembly checkpoint. The past few years have witnessed significant progress in understanding the quantitative mechanisms underlying these varied APC/C functions. This review integrates the overall functions and properties of the APC/C with mechanistic insights gained from recent cryo-electron microscopy (cryo-EM) studies of reconstituted human APC/C complexes.

scholarly journals Role for Human SIRT2 NAD-Dependent Deacetylase Activity in Control of Mitotic Exit in the Cell Cycle

2003 ◽  
Vol 23 (9) ◽  
pp. 3173-3185 ◽  
Author(s):  
Sylvia C. Dryden ◽  
Fatimah A. Nahhas ◽  
James E. Nowak ◽  
Anton-Scott Goustin ◽  
Michael A. Tainsky
Keyword(s):  
Cell Cycle ◽  
Protein A ◽  
Proteasome Inhibitors ◽  
26S Proteasome ◽  
Functional Studies ◽  
Cellular Life ◽  
Subsequent Decrease ◽  
Subsequent Degradation ◽  
Phosphorylation Cascade ◽  
And Control

ABSTRACT Studies of yeast have shown that the SIR2 gene family is involved in chromatin structure, transcriptional silencing, DNA repair, and control of cellular life span. Our functional studies of human SIRT2, a homolog of the product of the yeast SIR2 gene, indicate that it plays a role in mitosis. The SIRT2 protein is a NAD-dependent deacetylase (NDAC), the abundance of which increases dramatically during mitosis and is multiply phosphorylated at the G2/M transition of the cell cycle. Cells stably overexpressing the wild-type SIRT2 but not missense mutants lacking NDAC activity show a marked prolongation of the mitotic phase of the cell cycle. Overexpression of the protein phosphatase CDC14B, but not its close homolog CDC14A, results in dephosphorylation of SIRT2 with a subsequent decrease in the abundance of SIRT2 protein. A CDC14B mutant defective in catalyzing dephosphorylation fails to change the phosphorylation status or abundance of SIRT2 protein. Addition of 26S proteasome inhibitors to human cells increases the abundance of SIRT2 protein, indicating that SIRT2 is targeted for degradation by the 26S proteasome. Our data suggest that human SIRT2 is part of a phosphorylation cascade in which SIRT2 is phosphorylated late in G2, during M, and into the period of cytokinesis. CDC14B may provoke exit from mitosis coincident with the loss of SIRT2 via ubiquitination and subsequent degradation by the 26S proteasome.

The Xenopus protein kinase pEg2 associates with the centrosome in a cell cycle-dependent manner, binds to the spindle microtubules and is involved in bipolar mitotic spindle assembly

1998 ◽  
Vol 111 (5) ◽  
pp. 557-572 ◽  
Author(s):  
C. Roghi ◽  
R. Giet ◽  
R. Uzbekov ◽  
N. Morin ◽  
I. Chartrain ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Mitotic Spindle ◽  
Cultured Cells ◽  
Dependent Manner ◽  
Egg Extracts ◽  
Pericentriolar Material ◽  
Spindle Microtubules ◽  
Cycle Dependent

By differential screening of a Xenopus laevis egg cDNA library, we have isolated a 2,111 bp cDNA which corresponds to a maternal mRNA specifically deadenylated after fertilisation. This cDNA, called Eg2, encodes a 407 amino acid protein kinase. The pEg2 sequence shows significant identity with members of a new protein kinase sub-family which includes Aurora from Drosophila and Ipl1 (increase in ploidy-1) from budding yeast, enzymes involved in centrosome migration and chromosome segregation, respectively. A single 46 kDa polypeptide, which corresponds to the deduced molecular mass of pEg2, is immunodetected in Xenopus oocyte and egg extracts, as well as in lysates of Xenopus XL2 cultured cells. In XL2 cells, pEg2 is immunodetected only in S, G2 and M phases of the cell cycle, where it always localises to the centrosomal region of the cell. In addition, pEg2 ‘invades’ the microtubules at the poles of the mitotic spindle in metaphase and anaphase. Immunoelectron microscopy experiments show that pEg2 is located precisely around the pericentriolar material in prophase and on the spindle microtubules in anaphase. We also demonstrate that pEg2 binds directly to taxol stabilised microtubules in vitro. In addition, we show that the presence of microtubules during mitosis is not necessary for an association between pEg2 and the centrosome. Finally we show that a catalytically inactive pEg2 kinase stops the assembly of bipolar mitotic spindles in Xenopus egg extracts.

scholarly journals Intricate Regulatory Mechanisms of the Anaphase-Promoting Complex/Cyclosome and Its Role in Chromatin Regulation

2021 ◽  
Vol 9 ◽  
Author(s):  
Tatyana Bodrug ◽  
Kaeli A. Welsh ◽  
Megan Hinkle ◽  
Michael J. Emanuele ◽  
Nicholas G. Brown
Keyword(s):  
Cell Cycle ◽  
Signaling Pathways ◽  
Biological Process ◽  
Conformational Dynamics ◽  
Intimate Relationship ◽  
Regulatory Mechanisms ◽  
Cell Cycle Regulators ◽  
Chromatin Regulation ◽  
Anaphase Promoting Complex

The ubiquitin (Ub)-proteasome system is vital to nearly every biological process in eukaryotes. Specifically, the conjugation of Ub to target proteins by Ub ligases, such as the Anaphase-Promoting Complex/Cyclosome (APC/C), is paramount for cell cycle transitions as it leads to the irreversible destruction of cell cycle regulators by the proteasome. Through this activity, the RING Ub ligase APC/C governs mitosis, G1, and numerous aspects of neurobiology. Pioneering cryo-EM, biochemical reconstitution, and cell-based studies have illuminated many aspects of the conformational dynamics of this large, multi-subunit complex and the sophisticated regulation of APC/C function. More recent studies have revealed new mechanisms that selectively dictate APC/C activity and explore additional pathways that are controlled by APC/C-mediated ubiquitination, including an intimate relationship with chromatin regulation. These tasks go beyond the traditional cell cycle role historically ascribed to the APC/C. Here, we review these novel findings, examine the mechanistic implications of APC/C regulation, and discuss the role of the APC/C in previously unappreciated signaling pathways.

scholarly journals APC/C: current understanding and future perspectives

F1000Research ◽  
2019 ◽  
Vol 8 ◽  
pp. 725 ◽  
Author(s):  
Hiroyuki Yamano
Keyword(s):  
Cell Cycle ◽  
Molecular Mechanisms ◽  
Current Understanding ◽  
Historical Background ◽  
Cell Cycle Regulators ◽  
Anaphase Promoting Complex ◽  
Electron Microscopy Analysis ◽  
Cellular Machinery ◽  
The Many ◽  
Ubiquitin Conjugating Enzymes

The separation of sister chromatids at anaphase, which is regulated by an E3 ubiquitin ligase called the anaphase-promoting complex/cyclosome (APC/C), is arguably the most important irrevocable event during the cell cycle. The APC/C and cyclin-dependent kinase 1 (Cdk1) are just two of the many significant cell cycle regulators and exert control through ubiquitylation and phosphorylation, respectively. The temporal and spatial regulation of the APC/C is achieved by multiple mechanisms, including phosphorylation, interaction with the structurally related co-activators Cdc20 and Cdh1, loading of distinct E2 ubiquitin-conjugating enzymes, binding with inhibitors and differential affinities for various substrates. Since the discovery of APC/C 25 years ago, intensive studies have uncovered many aspects of APC/C regulation, but we are still far from a full understanding of this important cellular machinery. Recent high-resolution cryogenic electron microscopy analysis and reconstitution of the APC/C have greatly advanced our understanding of molecular mechanisms underpinning the enzymatic properties of APC/C. In this review, we will examine the historical background and current understanding of APC/C regulation.

scholarly journals Characterization of Brassica rapa RAP2.4-Related Proteins in Stress Response and as CUL3-Dependent E3 Ligase Substrates

Cells ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 336 ◽  
Author(s):  
Sutton Mooney ◽  
Raed Al-Saharin ◽  
Christina M. Choi ◽  
Kyle Tucker ◽  
Chase Beathard ◽  
...  
Keyword(s):  
Brassica Rapa ◽  
Stress Responses ◽  
Expression Patterns ◽  
Economic Value ◽  
E3 Ligase ◽  
26S Proteasome ◽  
Dependent Manner ◽  
E3 Ligases ◽  
Subsequent Degradation ◽  
Stress Dependent

The turnip Brassica rapa has important economic value and represents a good model system to study gene function in crop plants. ERF/AP2 transcription factors are a major group of proteins that are often involved in regulating stress-responses and developmental programs. Some ERF/AP2 proteins are targets of CULLIN3-based E3 ligases that use BTB/POZ-MATH proteins as substrate receptors. These receptors bind the transcription factor and facilitate their ubiquitylation and subsequent degradation via the 26S proteasome. Here, we show tissue and stress-dependent expression patterns for three Brassica rapa ERF/AP2 proteins that are closely related to Arabidopsis thaliana AtRAP2.4. Cloning of the Brassica genes showed that the corresponding proteins can assemble with a BPM protein and CULLIN3, and that they are instable in a 26S proteasome dependent manner. This work demonstrates the conserved nature of the ERF/AP2-CULLIN3-based E3 ligase interplay, and represents a first step to analyze their function in a commercially relevant crop plant.

scholarly journals Phosphorylation of the Anaphase-promoting Complex/Cdc27 Is Involved in TGF-β Signaling

2011 ◽  
Vol 286 (12) ◽  
pp. 10041-10050 ◽  
Author(s):  
Liyong Zhang ◽  
Takeo Fujita ◽  
George Wu ◽  
Xiao Xiao ◽  
Yong Wan
Keyword(s):  
Cell Cycle ◽  
Signal Transduction ◽  
Growth Inhibition ◽  
Cell Cycle Arrest ◽  
Signaling Pathway ◽  
Casein Kinase Ii ◽  
Casein Kinase ◽  
Anaphase Promoting Complex ◽  
Cycle Arrest ◽  
Subsequent Degradation

Loss of TGF-β-induced growth inhibition is a hallmark of many human tumors. Previous studies implied that activation of the anaphase-promoting complex (APC/cyclosome) is involved in the TGF-β signaling pathway, which facilitates the destruction of SnoN, a transcriptional co-suppressor, which leads in turn to the transactivation of TGF-β-responsive genes for cell cycle arrest. The function of APC was demonstrated in TGF-β signal transduction, but the mechanism by which it is activated in response to TGF-β signaling remains unclear. We report here that phosphorylation of Cdc27, a core subunit of APC, in response to TGF-β signaling can facilitate the activation of APC. We have demonstrated that casein kinase II (CKII) is involved in the phosphorylation of Cdc27 in response to TGF-β signaling. Depletion of CKII by shRNA abolishes the TGF-β-induced phosphorylation of Cdc27 and subsequent degradation of SnoN. Disruptive mutation of Cdc27 (S154A) attenuates TGF-β-induced SnoN degradation. In addition, expression of a phosphorylation-resistant Cdc27 mutant significantly attenuates TGF-β-induced growth inhibition. Together, the results suggest that phosphorylation of Cdc27 by CKII is involved in TGF-β-induced activation of APC.

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