scholarly journals Nek5 promotes centrosome integrity in interphase and loss of centrosome cohesion in mitosis

2015 ◽  
Vol 209 (3) ◽  
pp. 339-348 ◽  
Author(s):  
Suzanna L. Prosser ◽  
Navdeep K. Sahota ◽  
Laurence Pelletier ◽  
Ciaran G. Morrison ◽  
Andrew M. Fry
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Primary Cilia ◽  
Microtubule Nucleation ◽  
Cycle Progression ◽  
Spindle Formation ◽  
Mitotic Entry ◽  
Bipolar Spindle ◽  
Centrosome Separation

Nek5 is a poorly characterized member of the NIMA-related kinase family, other members of which play roles in cell cycle progression and primary cilia function. Here, we show that Nek5, similar to Nek2, localizes to the proximal ends of centrioles. Depletion of Nek5 or overexpression of kinase-inactive Nek5 caused unscheduled separation of centrosomes in interphase, a phenotype also observed upon overexpression of active Nek2. However, separated centrosomes that resulted from Nek5 depletion remained relatively close together, exhibited excess recruitment of the centrosome linker protein rootletin, and had reduced levels of Nek2. In addition, Nek5 depletion led to loss of PCM components, including γ-tubulin, pericentrin, and Cdk5Rap2, with centrosomes exhibiting reduced microtubule nucleation. Upon mitotic entry, Nek5-depleted cells inappropriately retained centrosome linker components and exhibited delayed centrosome separation and defective chromosome segregation. Hence, Nek5 is required for the loss of centrosome linker proteins and enhanced microtubule nucleation that lead to timely centrosome separation and bipolar spindle formation in mitosis.

scholarly journals Non‐redundant functions of H2A.Z.1 and H2A.Z.2 in chromosome segregation and cell cycle progression

EMBO Reports ◽  
2021 ◽  
Author(s):  
Raquel Sales‐Gil ◽  
Dorothee C Kommer ◽  
Ines J Castro ◽  
Hasnat A Amin ◽  
Veronica Vinciotti ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Redundant Functions

scholarly journals The decision to enter mitosis: feedback and redundancy in the mitotic entry network

2009 ◽  
Vol 185 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Arne Lindqvist ◽  
Verónica Rodríguez-Bravo ◽  
René H. Medema
Keyword(s):  
Cell Cycle ◽  
Normal Cell ◽  
Cell Cycle Progression ◽  
Feedback Loops ◽  
Cyclin B ◽  
Cycle Progression ◽  
Mitotic Entry ◽  
Different Levels ◽  
Normal Cell Cycle

The decision to enter mitosis is mediated by a network of proteins that regulate activation of the cyclin B–Cdk1 complex. Within this network, several positive feedback loops can amplify cyclin B–Cdk1 activation to ensure complete commitment to a mitotic state once the decision to enter mitosis has been made. However, evidence is accumulating that several components of the feedback loops are redundant for cyclin B–Cdk1 activation during normal cell division. Nonetheless, defined feedback loops become essential to promote mitotic entry when normal cell cycle progression is perturbed. Recent data has demonstrated that at least three Plk1-dependent feedback loops exist that enhance cyclin B–Cdk1 activation at different levels. In this review, we discuss the role of various feedback loops that regulate cyclin B–Cdk1 activation under different conditions, the timing of their activation, and the possible identity of the elusive trigger that controls mitotic entry in human cells.

scholarly journals Distinct Cell Cycle Timing Requirements for Extracellular Signal-Regulated Kinase and Phosphoinositide 3-Kinase Signaling Pathways in Somatic Cell Mitosis

2002 ◽  
Vol 22 (20) ◽  
pp. 7226-7241 ◽  
Author(s):  
Elisabeth C. Roberts ◽  
Paul S. Shapiro ◽  
Theresa Stines Nahreini ◽  
Gilles Pages ◽  
Jacques Pouyssegur ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Cyclin B1 ◽  
Erk Pathway ◽  
Cycle Progression ◽  
Mitotic Entry ◽  
Extracellular Signal Regulated Kinase ◽  
Extracellular Signal ◽  
Phosphoinositide 3 Kinase ◽  
And Function

ABSTRACT Mitogen-activated protein (MAP) kinase and phosphoinositide 3-kinase (PI3K) pathways are necessary for cell cycle progression into S phase; however the importance of these pathways after the restriction point is poorly understood. In this study, we examined the regulation and function of extracellular signal-regulated kinase (ERK) and PI3K during G2/M in synchronized HeLa and NIH 3T3 cells. Phosphorylation and activation of both the MAP kinase kinase/ERK and PI3K/Akt pathways occur in late S and persist until the end of mitosis. Signaling was rapidly reversed by cell-permeable inhibitors, indicating that both pathways are continuously activated and rapidly cycle between active and inactive states during G2/M. The serum-dependent behavior of PI3K/Akt versus ERK pathway activation indicates that their mechanisms of regulation differ during G2/M. Effects of cell-permeable inhibitors and dominant-negative mutants show that both pathways are needed for mitotic progression. However, inhibiting the PI3K pathway interferes with cdc2 activation, cyclin B1 expression, and mitotic entry, whereas inhibiting the ERK pathway interferes with mitotic entry but has little effect on cdc2 activation and cyclin B1 and retards progression from metaphase to anaphase. Thus, our study provides novel evidence that ERK and PI3K pathways both promote cell cycle progression during G2/M but have different regulatory mechanisms and function at distinct times.

scholarly journals Compartmentalized nodes control mitotic entry signaling in fission yeast

2013 ◽  
Vol 24 (12) ◽  
pp. 1872-1881 ◽  
Author(s):  
Lin Deng ◽  
James B. Moseley
Keyword(s):  
Cell Cycle ◽  
Cell Growth ◽  
Fission Yeast ◽  
Cell Polarity ◽  
Cell Cycle Progression ◽  
Interaction Network ◽  
Yeast Cells ◽  
Cell Cortex ◽  
Cycle Progression ◽  
Mitotic Entry

Cell cycle progression is coupled to cell growth, but the mechanisms that generate growth-dependent cell cycle progression remain unclear. Fission yeast cells enter into mitosis at a defined size due to the conserved cell cycle kinases Cdr1 and Cdr2, which localize to a set of cortical nodes in the cell middle. Cdr2 is regulated by the cell polarity kinase Pom1, suggesting that interactions between cell polarity proteins and the Cdr1-Cdr2 module might underlie the coordination of cell growth and division. To identify the molecular connections between Cdr1/2 and cell polarity, we performed a comprehensive pairwise yeast two-hybrid screen. From the resulting interaction network, we found that the protein Skb1 interacted with both Cdr1 and the Cdr1 inhibitory target Wee1. Skb1 inhibited mitotic entry through negative regulation of Cdr1 and localized to both the cytoplasm and a novel set of cortical nodes. Skb1 nodes were distinct structures from Cdr1/2 nodes, and artificial targeting of Skb1 to Cdr1/2 nodes delayed entry into mitosis. We propose that the formation of distinct node structures in the cell cortex controls signaling pathways to link cell growth and division.

Epigenetic dynamics across the cell cycle

2010 ◽  
Vol 48 ◽  
pp. 107-120 ◽  
Author(s):  
Tony Bou Kheir ◽  
Anders H. Lund
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Cell Cycle Progression ◽  
Current Knowledge ◽  
Chromatin Condensation ◽  
Chromatin Modifications ◽  
Cycle Progression ◽  
Daughter Cells ◽  
Mammalian Cell Cycle ◽  
Regulate Cell Cycle Progression

Progression of the mammalian cell cycle depends on correct timing and co-ordination of a series of events, which are managed by the cellular transcriptional machinery and epigenetic mechanisms governing genome accessibility. Epigenetic chromatin modifications are dynamic across the cell cycle, and are shown to influence and be influenced by cell-cycle progression. Chromatin modifiers regulate cell-cycle progression locally by controlling the expression of individual genes and globally by controlling chromatin condensation and chromosome segregation. The cell cycle, on the other hand, ensures a correct inheritance of epigenetic chromatin modifications to daughter cells. In this chapter, we summarize the current knowledge on the dynamics of epigenetic chromatin modifications during progression of the cell cycle.

A highly conserved centrosomal kinase, AIR-1, is required for accurate cell cycle progression and segregation of developmental factors in Caenorhabditis elegans embryos

Development ◽  
1998 ◽  
Vol 125 (22) ◽  
pp. 4391-4402 ◽  
Author(s):  
J.M. Schumacher ◽  
N. Ashcroft ◽  
P.J. Donovan ◽  
A. Golden
Keyword(s):  
Chromosome Segregation ◽  
Mitotic Spindle ◽  
Cell Cycle Progression ◽  
Cycle Progression ◽  
Centrosomal Protein ◽  
C Elegans ◽  
Developmental Factors ◽  
Centrosome Separation ◽  
Spindle Dynamics ◽  
Bipolar Spindles

S. cerevisiae Ipl1, Drosophila Aurora, and the mammalian centrosomal protein IAK-1 define a new subfamily of serine/threonine kinases that regulate chromosome segregation and mitotic spindle dynamics. Mutations in ipl1 and aurora result in the generation of severely aneuploid cells and, in the case of aurora, monopolar spindles arising from a failure in centrosome separation. Here we show that a related, essential protein from C. elegans, AIR-1 (Aurora/Ipl1 related), is localized to mitotic centrosomes. Disruption of AIR-1 protein expression in C. elegans embryos results in severe aneuploidy and embryonic lethality. Unlike aurora mutants, this aneuploidy does not arise from a failure in centrosome separation. Bipolar spindles are formed in the absence of AIR-1, but they appear to be disorganized and are nucleated by abnormal-looking centrosomes. In addition to its requirement during mitosis, AIR-1 may regulate microtubule-based developmental processes as well. Our data suggests AIR-1 plays a role in P-granule segregation and the association of the germline factor PIE-1 with centrosomes.

scholarly journals Cep57 and Cep57L1 maintain centriole engagement in interphase to ensure centriole duplication cycle

2021 ◽  
Vol 220 (3) ◽  
Author(s):  
Kei K. Ito ◽  
Koki Watanabe ◽  
Haruki Ishida ◽  
Kyohei Matsuhashi ◽  
Takumi Chinen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Copy Number ◽  
Cell Cycle Progression ◽  
Dependent Manner ◽  
Tight Control ◽  
Cycle Progression ◽  
Centriole Duplication ◽  
Duplication Cycle

Centrioles duplicate in interphase only once per cell cycle. Newly formed centrioles remain associated with their mother centrioles. The two centrioles disengage at the end of mitosis, which licenses centriole duplication in the next cell cycle. Therefore, timely centriole disengagement is critical for the proper centriole duplication cycle. However, the mechanisms underlying centriole engagement during interphase are poorly understood. Here, we show that Cep57 and Cep57L1 cooperatively maintain centriole engagement during interphase. Codepletion of Cep57 and Cep57L1 induces precocious centriole disengagement in interphase without compromising cell cycle progression. The disengaged daughter centrioles convert into centrosomes during interphase in a Plk1-dependent manner. Furthermore, the centrioles reduplicate and the centriole number increases, which results in chromosome segregation errors. Overall, these findings demonstrate that the maintenance of centriole engagement by Cep57 and Cep57L1 during interphase is crucial for the tight control of centriole copy number and thus for proper chromosome segregation.

scholarly journals Cep57 and Cep57L1 cooperatively maintain centriole engagement during interphase to ensure proper centriole duplication cycle

2020 ◽  
Author(s):  
Kei K. Ito ◽  
Koki Watanabe ◽  
Haruki Ishida ◽  
Kyohei Matsuhashi ◽  
Takumi Chinen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Chromosome Segregation ◽  
Copy Number ◽  
Cell Cycle Progression ◽  
Dependent Manner ◽  
Tight Control ◽  
Cycle Progression ◽  
Centriole Duplication ◽  
Duplication Cycle

Centrioles duplicate in the interphase only once per cell cycle. Newly formed centrioles remain associated with their mother centrioles. The two centrioles disengage at the end of mitosis, which licenses centriole duplication in the next cell cycle. Therefore, timely centriole disengagement is critical for the proper centriole duplication cycle. However, the mechanisms underlying centriole engagement during interphase are poorly understood. Here, we show that Cep57 and Cep57L1 cooperatively maintain centriole engagement during interphase. Co-depletion of Cep57 and Cep57L1 induces precocious centriole disengagement in the interphase without compromising cell cycle progression. The disengaged daughter centrioles convert into centrosomes during interphase in a Plk1-dependent manner. Furthermore, the centrioles reduplicate and the centriole number increases, which results in chromosome segregation errors. Overall, these findings demonstrate that the maintenance of centriole engagement by Cep57 and Cep57L1 during interphase is crucial for the tight control of centriole copy number and thus for proper chromosome segregation.

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