scholarly journals The master cell cycle regulator APC-Cdc20 regulates ciliary length and disassembly of the primary cilium

eLife ◽  
2014 ◽  
Vol 3 ◽  
Author(s):  
Weiping Wang ◽  
Tao Wu ◽  
Marc W Kirschner
Keyword(s):  
Cell Cycle ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Cell Cycle Control ◽  
Critical Role ◽  
Anaphase Promoting Complex ◽  
Serum Stimulation ◽  
Basic Biology ◽  
The Stability

The primary cilium has an important role in signaling; defects in structure are associated with a variety of human diseases. Much of the most basic biology of this organelle is poorly understood, even basic mechanisms, such as control of growth and resorption. We show that the activity of the anaphase-promoting complex (APC), an E3 that regulates the onset of anaphase, destabilizes axonemal microtubules in the primary cilium. Furthermore, the metaphase APC co-activator, Cdc20, is specifically recruited to the basal body of primary cilia. Inhibition of APC-Cdc20 activity increases the ciliary length, while overexpression of Cdc20 suppresses cilium formation. APC-Cdc20 activity is required for the timely resorption of the cilium after serum stimulation. In addition, APC regulates the stability of axonemal microtubules through targeting Nek1, the ciliary kinase, for proteolysis. These data demonstrate a novel function of APC beyond cell cycle control and implicate critical role of ubiquitin-mediated proteolysis in ciliary disassembly.

Abstract P119: S100A6 Regulates Endothelial Cell Physiology

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Shumei Ren ◽  
Karsten Peppel ◽  
Patrick Most
Keyword(s):  
Cell Cycle ◽  
Endothelial Cell ◽  
Protein Function ◽  
Cell Cycle Control ◽  
Tube Formation ◽  
Cell Physiology ◽  
Ki 67 ◽  
Proliferation Markers ◽  
Serum Stimulation

Endothelial cell dysfunction is central to the development of cardiovascular pathologies. While Calcium cycling is of recognized importance to myocyte physiology and cardiac perfomance, the role of Ca2+ signaling in endothelial cell (EC) physiology remains relatively unexplored. In this study we investigated the role of S100A6 (calcyclin), an EF-hand type Ca2+ -binding protein that modulates target protein function dependent upon intracellular Ca2+ signaling. S100A6 displays cytoplasmic distribution in quiescent, confluent HUVEC, but translocates to the nucleus upon serum stimulation. Oxidative stress, induced by incubation of HUVEC with H¬2O2 (150 uM) leads to redistribution of nuclear S100A6 to the cytosol and cell cycle arrest. Knockdown of S100A6 by siRNA transfection reduced S100A6 levels by over 70% and diminished DNA synthesis by more than 75% (±12%, n=9, p<0.01), as well as expression of the proliferation markers PCNA and KI-67 (by more than 70% (±15%, n=9, p<0.01). Reduced S100A6 levels in HUVEC lead to an increase in cellular senescence, as measured by the expression of senescence associated β-galactosidase expression (by more than 6-fold, n=4, p<0.01) and a reduction of EC tube formation on matrigel matrix (by more than 90%, n=3, p<0.01). Reduction of S100A6 increased the expression of the cell cycle control and DNA repair-associated gene BRCA2, but did not change in the expression of BRCA1, cyclins or p53 (by RT-PCR array). We conclude that Ca2+ regulation by S100A6 is essential for multiple aspects of EC physiology.

scholarly journals Cell Cycle Control of Cdc7p Kinase Activity through Regulation of Dbf4p Stability

1999 ◽  
Vol 19 (7) ◽  
pp. 4888-4896 ◽  
Author(s):  
Guy Oshiro ◽  
Julia C. Owens ◽  
Yiqun Shellman ◽  
Robert A. Sclafani ◽  
Joachim J. Li
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Dna Replication ◽  
Kinase Activity ◽  
Cell Cycle Control ◽  
S Phase ◽  
Regulatory Subunit ◽  
Anaphase Promoting Complex ◽  
Initiation Of Dna Replication

ABSTRACT In Saccharomyces cerevisiae, the heteromeric kinase complex Cdc7p-Dbf4p plays a pivotal role at replication origins in triggering the initiation of DNA replication during the S phase. We have assayed the kinase activity of endogenous levels of Cdc7p kinase by using a likely physiological target, Mcm2p, as a substrate. Using this assay, we have confirmed that Cdc7p kinase activity fluctuates during the cell cycle; it is low in the G1 phase, rises as cells enter the S phase, and remains high until cells complete mitosis. These changes in kinase activity cannot be accounted for by changes in the levels of the catalytic subunit Cdc7p, as these levels are constant during the cell cycle. However, the fluctuations in kinase activity do correlate with levels of the regulatory subunit Dbf4p. The regulation of Dbf4p levels can be attributed in part to increased degradation of the protein in G1 cells. This G1-phase instability is cdc16 dependent, suggesting a role of the anaphase-promoting complex in the turnover of Dbf4p. Overexpression of Dbf4p in the G1 phase can partially overcome this elevated turnover and lead to an increase in Cdc7p kinase activity. Thus, the regulation of Dbf4p levels through the control of Dbf4p degradation has an important role in the regulation of Cdc7p kinase activity during the cell cycle.

scholarly journals Transient primary cilia mediate robust Hedgehog pathway-dependent cell cycle control

2019 ◽  
Author(s):  
Emily K. Ho ◽  
Anaïs E. Tsai ◽  
Tim Stearns
Keyword(s):  
Cell Cycle ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Cell Cycle Control ◽  
Proliferating Cells ◽  
Pathway Activity ◽  
Cell Cycles ◽  
Medulloblastoma Cell Line ◽  
Multiple Cell ◽  
Hh Signaling

SummaryThe regulation of proliferation is one of the primary functions of Hedgehog (Hh) signaling in development. Transduction of Hh signaling requires the primary cilium, a microtubule-based organelle that is necessary for several steps in the pathway (Corbit et al., 2005; Huangfu and Anderson, 2005; Huangfu et al., 2003; Liu et al., 2005; Rohatgi et al., 2007). Many cells only build a primary cilium upon cell cycle arrest in G0. In those proliferating cells that do make a cilium, it is a transient organelle, being assembled in G1 and disassembled sometime after, although exactly when is not well-characterized (Ford et al., 2018; Pugacheva et al., 2007; Wang and Dynlacht, 2018). Thus the requirement for primary cilia presents a conundrum: how are proliferative signals conveyed through an organelle that is present for only part of the cell cycle? Here we investigate this question in a mouse medulloblastoma cell line, SMB55, that requires cilium-mediated Hh pathway activity for proliferation (Zhao et al., 2015). We show that SMB55 cells are often ciliated beyond G1 into S phase, and the presence of the cilium determines the periods of Hh pathway activity. Using live imaging over multiple cell cycles, we define two windows of opportunity for Hh pathway activity, either of which is sufficient to effect cell cycle entry. The first is in the ciliated phase of the previous cell cycle, and the second is in G1 of the cell cycle in which the decision is made. We propose that the ability of cells to integrate Hh pathway activity from more than one cell cycle imparts robustness on Hh pathway control of proliferation and may have implications for other Hh-mediated events in development.

scholarly journals Phosphorylation of the Anaphase Promoting Complex activator CDH1/FZR regulates the transition from Meiosis I to Meiosis II in mouse male germ cell

2020 ◽  
Author(s):  
Nobuhiro Tanno ◽  
Shinji Kuninaka ◽  
Sayoko Fujimura ◽  
Kaho Okamura ◽  
Kazumasa Takemoto ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Germ Cells ◽  
Critical Role ◽  
Biological Significance ◽  
Mitotic Cell ◽  
Anaphase Promoting Complex ◽  
Meiosis I

SummaryCDH1/FZR is an activator of Anaphase promoting complex/Cyclosome (APC/C), best known for its role as E3 ubiquitin ligase that drives the cell cycle. APC/C activity is regulated by CDK-mediated phosphorylation of CDH1 during mitotic cell cycle. Although the critical role of CDH1 phosphorylation has been shown mainly in yeast and in vitro cell culture studies, its biological significance in mammalian tissues in vivo remained elusive. Here, we examined the in vivo role of CDH1 phosphorylation using a mouse model, in which non-phosphorylatable substitutions were introduced in the putative CDK-phosphorylation sites of CDH1. Although ablation of CDH1 phosphorylation did not show substantial consequences in mouse somatic tissues, it led to severe testicular defects resulting in male infertility. In the absence of CDH1 phosphorylation, male juvenile germ cells entered meiosis normally but skipped meiosis II producing diploid spermatid-like cells. In aged testis, male germ cells were overall abolished, showing Sertoli cell-only phenotype. The present study demonstrated that phosphorylation of CDH1 is required for temporal regulation of APC/C activity at the transition from meiosis I to meiosis II, and for spermatoginial stem cell maintenance, which raised an insight into the sexual dimorphism of CDH1-regulation in germ cells.

scholarly journals The Role of Cdh1p in Maintaining Genomic Stability in Budding Yeast

Genetics ◽  
2003 ◽  
Vol 165 (2) ◽  
pp. 489-503 ◽  
Author(s):  
Karen E Ross ◽  
Orna Cohen-Fix
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Spindle Assembly Checkpoint ◽  
Chromosome Loss ◽  
Cyclin Dependent Kinase ◽  
Anaphase Promoting Complex ◽  
Growth Defects ◽  
Genes Encoding ◽  
Specificity Factor

Abstract Cdh1p, a substrate specificity factor for the cell cycle-regulated ubiquitin ligase, the anaphase-promoting complex/cyclosome (APC/C), promotes exit from mitosis by directing the degradation of a number of proteins, including the mitotic cyclins. Here we present evidence that Cdh1p activity at the M/G1 transition is important not only for mitotic exit but also for high-fidelity chromosome segregation in the subsequent cell cycle. CDH1 showed genetic interactions with MAD2 and PDS1, genes encoding components of the mitotic spindle assembly checkpoint that acts at metaphase to prevent premature chromosome segregation. Unlike cdh1Δ and mad2Δ single mutants, the mad2Δ cdh1Δ double mutant grew slowly and exhibited high rates of chromosome and plasmid loss. Simultaneous deletion of PDS1 and CDH1 caused extensive chromosome missegregation and cell death. Our data suggest that at least part of the chromosome loss can be attributed to kinetochore/spindle problems. Our data further suggest that Cdh1p and Sic1p, a Cdc28p/Clb inhibitor, have overlapping as well as nonoverlapping roles in ensuring proper chromosome segregation. The severe growth defects of both mad2Δ cdh1Δ and pds1Δ cdh1Δ strains were rescued by overexpressing Swe1p, a G2/M inhibitor of the cyclin-dependent kinase, Cdc28p/Clb. We propose that the failure to degrade cyclins at the end of mitosis leaves cdh1Δ mutant strains with abnormal Cdc28p/Clb activity that interferes with proper chromosome segregation.

scholarly journals Cell Cycle-Dependent Expression of Mammalian E2-C Regulated by the Anaphase-Promoting Complex/Cyclosome

2000 ◽  
Vol 11 (8) ◽  
pp. 2821-2831 ◽  
Author(s):  
Atsushi Yamanaka ◽  
Shigetsugu Hatakeyama ◽  
Kin-ichiro Kominami ◽  
Masatoshi Kitagawa ◽  
Masaki Matsumoto ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Substrate Specificity ◽  
Critical Role ◽  
Anaphase Promoting Complex ◽  
Polyubiquitin Chain ◽  
M Phase ◽  
Ubiquitin Conjugating Enzyme ◽  
Recognition Motifs ◽  
Cycle Dependent ◽  
Conjugating Enzyme

Progression through mitosis requires the precisely timed ubiquitin-dependent degradation of specific substrates. E2-C is a ubiquitin-conjugating enzyme that plays a critical role with anaphase-promoting complex/cyclosome (APC/C) in progression of and exit from M phase. Here we report that mammalian E2-C is expressed in late G2/M phase and is degraded as cells exit from M phase. The mammalian E2-C shows an autoubiquitinating activity leading to covalent conjugation to itself with several ubiquitins. The ubiquitination of E2-C is strongly enhanced by APC/C, resulting in the formation of a polyubiquitin chain. The polyubiquitination of mammalian E2-C occurs only when cells exit from M phase. Furthermore, mammalian E2-C contains two putative destruction boxes that are believed to act as recognition motifs for APC/C. The mutation of this motif reduced the polyubiquitination of mammalian E2-C, resulting in its stabilization. These results suggest that mammalian E2-C is itself a substrate of the APC/C-dependent proteolysis machinery, and that the periodic expression of mammalian E2-C may be a novel autoregulatory system for the control of the APC/C activity and its substrate specificity.

The role of MCM proteins in the cell cycle control of genome duplication

BioEssays ◽  
1996 ◽  
Vol 18 (3) ◽  
pp. 183-190 ◽  
Author(s):  
Stephen E. Kearsey ◽  
Domenico Maiorano ◽  
Eddie C. Holmes ◽  
Ivan T. Todorov
Keyword(s):  
Cell Cycle ◽  
Genome Duplication ◽  
Cell Cycle Control ◽  
Mcm Proteins

scholarly journals A Model for Primary Cilium Biogenesis by Polarized Epithelial Cells: Role of the Midbody Remnant and Associated Specialized Membranes

2021 ◽  
Vol 8 ◽  
Author(s):  
Leticia Labat-de-Hoz ◽  
Armando Rubio-Ramos ◽  
Javier Casares-Arias ◽  
Miguel Bernabé-Rubio ◽  
Isabel Correas ◽  
...  
Keyword(s):  
Cell Surface ◽  
Primary Cilium ◽  
Primary Cilia ◽  
Control Cell ◽  
Future Research ◽  
Alternative Route ◽  
Ciliary Membrane ◽  
Cilium Formation ◽  
Membrane Compartmentalization

Primary cilia are solitary, microtubule-based protrusions surrounded by a ciliary membrane equipped with selected receptors that orchestrate important signaling pathways that control cell growth, differentiation, development and homeostasis. Depending on the cell type, primary cilium assembly takes place intracellularly or at the cell surface. The intracellular route has been the focus of research on primary cilium biogenesis, whereas the route that occurs at the cell surface, which we call the “alternative” route, has been much less thoroughly characterized. In this review, based on recent experimental evidence, we present a model of primary ciliogenesis by the alternative route in which the remnant of the midbody generated upon cytokinesis acquires compact membranes, that are involved in compartmentalization of biological membranes. The midbody remnant delivers part of those membranes to the centrosome in order to assemble the ciliary membrane, thereby licensing primary cilium formation. The midbody remnant's involvement in primary cilium formation, the regulation of its inheritance by the ESCRT machinery, and the assembly of the ciliary membrane from the membranes originally associated with the remnant are discussed in the context of the literature concerning the ciliary membrane, the emerging roles of the midbody remnant, the regulation of cytokinesis, and the role of membrane compartmentalization. We also present a model of cilium emergence during evolution, and summarize the directions for future research.

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