scholarly journals Effect of Water Stress on Cell Division and Cdc2-Like Cell Cycle Kinase Activity in Wheat Leaves

1998 ◽  
Vol 117 (2) ◽  
pp. 667-678 ◽  
Author(s):  
Ute Schuppler ◽  
Ping-Hua He ◽  
Peter C.L. John ◽  
Rana Munns
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Water Stress ◽  
Kinase Activity ◽  
Effect Of Water ◽  
Wheat Leaves ◽  
Cell Cycle Kinase

scholarly journals Specific Inhibition of Elm1 Kinase Activity Reveals Functions Required for Early G1 Events

2003 ◽  
Vol 23 (17) ◽  
pp. 6327-6337 ◽  
Author(s):  
Aparna Sreenivasan ◽  
Anthony C. Bishop ◽  
Kevan M. Shokat ◽  
Douglas R. Kellogg
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Cell Growth ◽  
Kinase Activity ◽  
Budding Yeast ◽  
Specific Inhibition ◽  
Bud Emergence ◽  
Wee1 Kinase ◽  
Yeast Homolog

ABSTRACT In budding yeast, the Elm1 kinase is required for coordination of cell growth and cell division at G2/M. Elm1 is also required for efficient cytokinesis and for regulation of Swe1, the budding yeast homolog of the Wee1 kinase. To further characterize Elm1 function, we engineered an ELM1 allele that can be rapidly and selectively inhibited in vivo. We found that inhibition of Elm1 kinase activity during G2 results in a phenotype similar to the phenotype caused by deletion of the ELM1 gene, as expected. However, inhibition of Elm1 kinase activity earlier in the cell cycle results in a prolonged G1 delay. The G1 requirement for Elm1 kinase activity occurs before bud emergence, polarization of the septins, and synthesis of G1 cyclins. Inhibition of Elm1 kinase activity during early G1 also causes defects in the organization of septins, and inhibition of Elm1 kinase activity in a strain lacking the redundant G1 cyclins CLN1 and CLN2 is lethal. These results demonstrate that the Elm1 kinase plays an important role in G1 events required for bud emergence and septin organization.

scholarly journals A novel mammalian protein, p55CDC, present in dividing cells is associated with protein kinase activity and has homology to the Saccharomyces cerevisiae cell division cycle proteins Cdc20 and Cdc4.

1994 ◽  
Vol 14 (5) ◽  
pp. 3350-3363 ◽  
Author(s):  
J Weinstein ◽  
F W Jacobsen ◽  
J Hsu-Chen ◽  
T Wu ◽  
L G Baum
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Protein Kinase ◽  
Mammalian Cells ◽  
Kinase Activity ◽  
Yeast Cells ◽  
Protein Kinase Activity ◽  
Growing Cell ◽  
Dividing Cells

A novel protein, p55CDC, has been identified in cycling mammalian cells. This transcript is readily detectable in all exponentially growing cell lines but disappears when cells are chemically induced to fall out of the cell cycle and differentiate. The p55CDC protein appears to be essential for cell division, since transfection of antisense p55CDC cDNA into CHO cells resulted in isolation of only those cells which exhibited a compensatory increase in p55CDC transcripts in the sense orientation. Immunoprecipitation of p55CDC yielded protein complexes with kinase activity which fluctuated during the cell cycle. Since p55CDC does not have the conserved protein kinase domains, this activity must be due to one or more of the associated proteins in the immune complex. The highest levels of protein kinase activity were seen with alpha-casein and myelin basic protein as substrates and demonstrated a pattern of activity distinct from that described for the known cyclin-dependent cell division kinases. The p55CDC protein was also phosphorylated in dividing cells. The amino acid sequence of p55CDC contains seven repeats homologous to the beta subunit of G proteins, and the highest degree of homology in these repeats was found with the Saccharomyces cerevisiae Cdc20 and Cdc4 proteins, which have been proposed to be involved in the formation of a functional bipolar mitotic spindle in yeast cells. The G beta repeat has been postulated to mediate protein-protein interactions and, in p55CDC, may modulate its association with a unique cell cycle protein kinase. These findings suggest that p55CDC is a component of the mammalian cell cycle mechanism.

Effect of water stress upon cell division in root tips oferagrostis carvula (SCHRAD.) NEES

1990 ◽  
Vol 32 (2) ◽  
pp. 153-160 ◽  
Author(s):  
G. V. Echenique ◽  
N. R. Curvetto
Keyword(s):  
Cell Division ◽  
Water Stress ◽  
Root Tips ◽  
Effect Of Water

scholarly journals CDKD-dependent activation of CDKA;1 controls microtubule dynamics and cytokinesis during meiosis

2020 ◽  
Vol 219 (8) ◽  
Author(s):  
Kostika Sofroni ◽  
Hirotomo Takatsuka ◽  
Chao Yang ◽  
Nico Dissmeyer ◽  
Shinichiro Komaki ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Kinase Activity ◽  
Nuclear Division ◽  
Cyclin Dependent Kinase ◽  
Loss Of Function ◽  
Precise Control ◽  
Fine Grained ◽  
Cytoskeleton Dynamics ◽  
Cell Cycle Regulator Cyclin ◽  
Cell Cycle Kinase

Precise control of cytoskeleton dynamics and its tight coordination with chromosomal events are key to cell division. This is exemplified by formation of the spindle and execution of cytokinesis after nuclear division. Here, we reveal that the central cell cycle regulator CYCLIN DEPENDENT KINASE A;1 (CDKA;1), the Arabidopsis homologue of Cdk1 and Cdk2, partially in conjunction with CYCLIN B3;1 (CYCB3;1), is a key regulator of the microtubule cytoskeleton in meiosis. For full CDKA;1 activity, the function of three redundantly acting CDK-activating kinases (CAKs), CDKD;1, CDKD;2, and CDKD;3, is necessary. Progressive loss of these genes in combination with a weak loss-of-function mutant in CDKA;1 allowed a fine-grained dissection of the requirement of cell-cycle kinase activity for meiosis. Notably, a moderate reduction of CDKA;1 activity converts the simultaneous cytokinesis in Arabidopsis, i.e., one cytokinesis separating all four meiotic products concurrently into two successive cytokineses with cell wall formation after the first and second meiotic division, as found in many monocotyledonous species.

scholarly journals Cdk2 catalytic activity is essential for meiotic cell division in vivo

2016 ◽  
Vol 473 (18) ◽  
pp. 2783-2798 ◽  
Author(s):  
Sangeeta Chauhan ◽  
M. Kasim Diril ◽  
Joanna H.S. Lee ◽  
Xavier Bisteau ◽  
Vanessa Manoharan ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Kinase Activity ◽  
Gene Knockout ◽  
Mitotic Cell ◽  
Regulatory Proteins ◽  
Mouse Strains ◽  
Meiotic Cell ◽  
Independent Functions

Cyclin-dependent kinases (Cdks) control the eukaryotic cell cycle by phosphorylating serine and threonine residues in key regulatory proteins, but some Cdk family members may exert kinase-independent functions that cannot easily be assessed using gene knockout approaches. While Cdk2-deficient mice display near-normal mitotic cell proliferation due to the compensatory activities of Cdk1 and Cdk4, they are unable to undergo meiotic generation of gametes and are consequently sterile. To investigate whether Cdk2 regulates meiosis via protein phosphorylation or by alternative kinase-independent mechanisms, we generated two different knockin mouse strains in which Cdk2 point mutations ablated enzyme activity without altering protein expression levels. Mice homozygous for the mutations Cdk2D145N/D145N or Cdk2T160A/T160A expressed only ‘kinase-dead’ variants of Cdk2 under the control of the endogenous promoter, and despite exhibiting normal expression of cell cycle regulatory proteins and complexes, both mutations rendered mice sterile. Mouse cells that expressed only ‘kinase-dead’ variants of Cdk2 displayed normal mitotic cell cycle progression and proliferation both in vitro and in vivo, indicating that loss of Cdk2 kinase activity exerted little effect on this mode of cell division. In contrast, the reproductive organs of Cdk2 mutant mice exhibited abnormal morphology and impaired function associated with defective meiotic cell division and inability to produce gametes. Cdk2 mutant animals were therefore comparable to gene knockout mice, which completely lack the Cdk2 protein. Together, our data indicate that the essential meiotic functions of Cdk2 depend on its kinase activity, without which the generation of haploid cells is disrupted, resulting in sterility of otherwise healthy animals.

A novel mammalian protein, p55CDC, present in dividing cells is associated with protein kinase activity and has homology to the Saccharomyces cerevisiae cell division cycle proteins Cdc20 and Cdc4

1994 ◽  
Vol 14 (5) ◽  
pp. 3350-3363
Author(s):  
J Weinstein ◽  
F W Jacobsen ◽  
J Hsu-Chen ◽  
T Wu ◽  
L G Baum
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Cell Cycle ◽  
Cell Division ◽  
Protein Kinase ◽  
Mammalian Cells ◽  
Kinase Activity ◽  
Yeast Cells ◽  
Protein Kinase Activity ◽  
Growing Cell ◽  
Dividing Cells

A novel protein, p55CDC, has been identified in cycling mammalian cells. This transcript is readily detectable in all exponentially growing cell lines but disappears when cells are chemically induced to fall out of the cell cycle and differentiate. The p55CDC protein appears to be essential for cell division, since transfection of antisense p55CDC cDNA into CHO cells resulted in isolation of only those cells which exhibited a compensatory increase in p55CDC transcripts in the sense orientation. Immunoprecipitation of p55CDC yielded protein complexes with kinase activity which fluctuated during the cell cycle. Since p55CDC does not have the conserved protein kinase domains, this activity must be due to one or more of the associated proteins in the immune complex. The highest levels of protein kinase activity were seen with alpha-casein and myelin basic protein as substrates and demonstrated a pattern of activity distinct from that described for the known cyclin-dependent cell division kinases. The p55CDC protein was also phosphorylated in dividing cells. The amino acid sequence of p55CDC contains seven repeats homologous to the beta subunit of G proteins, and the highest degree of homology in these repeats was found with the Saccharomyces cerevisiae Cdc20 and Cdc4 proteins, which have been proposed to be involved in the formation of a functional bipolar mitotic spindle in yeast cells. The G beta repeat has been postulated to mediate protein-protein interactions and, in p55CDC, may modulate its association with a unique cell cycle protein kinase. These findings suggest that p55CDC is a component of the mammalian cell cycle mechanism.

scholarly journals Nek2 kinase displaces distal appendages from the mother centriole prior to mitosis

2020 ◽  
Vol 219 (3) ◽  
Author(s):  
Linda Viol ◽  
Shoji Hata ◽  
Ana Pastor-Peidro ◽  
Annett Neuner ◽  
Florian Murke ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Division ◽  
Kinase Activity ◽  
Mammary Epithelial Cells ◽  
Mammary Epithelial ◽  
Pigment Epithelial ◽  
Mother Centriole ◽  
G0 Phase ◽  
Signaling Components ◽  
Ciliary Signaling

Distal appendages (DAs) of the mother centriole are essential for the initial steps of ciliogenesis in G1/G0 phase of the cell cycle. DAs are released from centrosomes in mitosis by an undefined mechanism. Here, we show that specific DAs lose their centrosomal localization at the G2/M transition in a manner that relies upon Nek2 kinase activity to ensure low DA levels at mitotic centrosomes. Overexpression of active Nek2A, but not kinase-dead Nek2A, prematurely displaced DAs from the interphase centrosomes of immortalized retina pigment epithelial (RPE1) cells. This dramatic impact was also observed in mammary epithelial cells with constitutively high levels of Nek2. Conversely, Nek2 knockout led to incomplete dissociation of DAs and cilia in mitosis. As a consequence, we observed the presence of a cilia remnant that promoted the asymmetric inheritance of ciliary signaling components and supported cilium reassembly after cell division. Together, our data establish Nek2 as an important kinase that regulates DAs before mitosis.

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