A Role for the Common GTP-Binding Protein in Coupling of Chromosome Replication to Cell Growth and Cell Division

2002 ◽  
Vol 292 (2) ◽  
pp. 333-338 ◽  
Author(s):  
Aleksandra Sikora-Borgula ◽  
Monika Słomińska ◽  
Piotr Trzonkowski ◽  
Ryszard Zielke ◽  
Andrzej Myśliwski ◽  
...  
Keyword(s):  
Cell Division ◽  
Cell Growth ◽  
Binding Protein ◽  
Chromosome Replication ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
The Common

Impaired chromosome partitioning and synchronization of DNA replication initiation in an insertional mutant in the Vibrio harveyi cgtA gene coding for a common GTP-binding protein

2002 ◽  
Vol 362 (3) ◽  
pp. 579-584 ◽  
Author(s):  
Monika SŁOMIṄSKA ◽  
Grażyna KONOPA ◽  
Grzegorz WĘGRZYN ◽  
Agata CZYŻ
Keyword(s):  
Cell Division ◽  
Gene Product ◽  
Vibrio Harveyi ◽  
Binding Protein ◽  
Chromosome Replication ◽  
Replication Initiation ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Insertional Mutant ◽  
Chromosome Partitioning

The Vibrio harveyi cgtA gene product belongs to a subfamily of small GTP-binding proteins, called Obg-like proteins. Members of this subfamily are present in diverse organisms ranging from bacteria to humans. On the other hand, the functions of these proteins in the regulation of cellular processes are largely unknown. Genes coding for these proteins are essential in almost all bacteria investigated thus far. However, a viable V. harveyi insertional mutant in the cgtA gene was described recently. Therefore, this mutant gives a unique opportunity to study functions of a member of the subfamily of Obg-like proteins. Here we demonstrate that the mutant cells often form long filaments with expanded, non-partitioned or rarely partitioned chromosomes. Such a phenotype suggests impairment of the mechanism of chromosome partition. Flow cytometric studies revealed that synchronization of chromosome replication initiation is also significantly disturbed in the cgtA mutant. Moreover, in contrast to wild-type V. harveyi, inhibition of chromosome replication and/or of cell division in the mutant bacteria caused significant increase in the number of large cells, suggesting that the cgtA gene product may be involved in the coupling of cell growth to chromosome replication and cell division. These results indicate that CgtA, an Obg-like GTP-binding protein, plays an important role in the regulation of chromosomal functions.

Escherichia coli cell-division gene ftsZ encodes a novel GTP-binding protein

Nature ◽  
1992 ◽  
Vol 359 (6392) ◽  
pp. 251-254 ◽  
Author(s):  
Debabrata RayChaudhuri ◽  
James T. Park
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Binding Protein ◽  
Coli Cell ◽  
Gtp Binding Protein ◽  
Gtp Binding

scholarly journals The hydroxyurea-induced small GTP-binding protein SAR modulates γ-globin gene expression in human erythroid cells

Blood ◽  
2005 ◽  
Vol 106 (9) ◽  
pp. 3256-3263 ◽  
Author(s):  
Delia C. Tang ◽  
Jianqiong Zhu ◽  
Wenli Liu ◽  
Kyung Chin ◽  
Jun Sun ◽  
...  
Keyword(s):  
Cell Growth ◽  
Molecular Mechanisms ◽  
Binding Protein ◽  
Globin Gene ◽  
K562 Cells ◽  
Pi3 Kinase ◽  
Erythroid Cell ◽  
Erythroid Cells ◽  
Gtp Binding Protein ◽  
Gtp Binding

AbstractHydroxyurea (HU), a drug effective in the treatment of sickle cell disease, is thought to indirectly promote fetal hemoglobin (Hb F) production by perturbing the maturation of erythroid precursors. The molecular mechanisms involved in HU-mediated regulation of γ-globin expression are currently unclear. We identified an HU-induced small guanosine triphosphate (GTP)–binding protein, secretion-associated and RAS-related (SAR) protein, in adult erythroid cells using differential display. Stable SAR expression in K562 cells increased γ-globin mRNA expression and resulted in macrocytosis. The cells appeared immature. SAR-mediated induction of γ-globin also inhibited K562 cell growth by causing arrest in G1/S, apoptosis, and delay of maturation, cellular changes consistent with the previously known effects of HU on erythroid cells. SAR also enhanced both γ- and β-globin transcription in primary bone marrow CD34+ cells, with a greater effect on γ-globin than on β-globin. Although up-regulation of GATA-2 and p21 was observed both in SAR-expressing cells and HU-treated K562 cells, phosphatidylinositol 3 (PI3) kinase and phosphorylated ERK were inhibited specifically in SAR-expressing cells. These data reveal a novel role of SAR distinct from its previously known protein-trafficking function. We suggest that SAR may participate in both erythroid cell growth and γ-globin production by regulating PI3 kinase/extracellular protein–related kinase (ERK) and GATA-2/p21-dependent signal transduction pathways.

scholarly journals DRG2 Accelerates Senescence via Negative Regulation of SIRT1 in Human Diploid Fibroblasts

2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Bing Si Li ◽  
Ai Lin Jin ◽  
ZiQi Zhou ◽  
Jae Ho Seo ◽  
Byung-Min Choi
Keyword(s):  
Oxidative Stress ◽  
Cell Growth ◽  
Binding Protein ◽  
Ectopic Expression ◽  
Sirtuin 1 ◽  
Premature Senescence ◽  
Gtp Binding Protein ◽  
Human Diploid Fibroblasts ◽  
Gtp Binding ◽  
Stress Induced Premature Senescence

Accumulating evidence suggests that developmentally regulated GTP-binding protein 2 (DRG2), an evolutionarily conserved GTP-binding protein, plays an important role in regulating cell growth, inflammation, and mitochondria dynamics. However, the effect of DRG2 in aging remains unclear. In this study, we found that endogenous DRG2 protein expression is upregulated in oxidative stress-induced premature senescence models and tissues of aged mice. Ectopic expression of DRG2 significantly promoted senescence-associated β-galactosidase (SA-β-gal) activity and inhibited cell growth, concomitant with increase in levels of acetyl (ac)-p53 (Lys382), ac-nuclear factor-kB (NF-κB) p65 (Lys310), p21Waf1/Cip1, and p16Ink4a and a decrease in cyclin D1. In this process, reactive oxygen species (ROS) and phosphorylation of H2A histone family member X (H2A.X), forming γ-H2A.X, were enhanced. Mechanistically, ectopic expression of DRG2 downregulated Sirtuin-1 (SIRT1), resulting in augmented acetylation of p53 and NF-κB p65. Additionally, DRG2 knockdown significantly abolished oxidative stress-induced premature senescence. Our results provide a possible molecular mechanism for investigation of cellular senescence and aging regulated by DRG2.

Recruitment of the Earliest Component of the Bacterial Flagellum to the Old Cell Division Pole by a Membrane-Associated Signal Recognition Particle Family GTP-Binding Protein

2009 ◽  
Vol 391 (4) ◽  
pp. 679-690 ◽  
Author(s):  
Johnathan C.D. Green ◽  
Christina Kahramanoglou ◽  
Alamgir Rahman ◽  
Alexandra M.C. Pender ◽  
Nicolas Charbonnel ◽  
...  
Keyword(s):  
Cell Division ◽  
Binding Protein ◽  
Signal Recognition Particle ◽  
Signal Recognition ◽  
Gtp Binding Protein ◽  
Bacterial Flagellum ◽  
Gtp Binding

Small GTP-binding Protein RalA Associates with Weibel-Palade Bodies in Endothelial Cells

1999 ◽  
Vol 82 (09) ◽  
pp. 1177-1181 ◽  
Author(s):  
Hubert de Leeuw ◽  
Pauline Wijers-Koster ◽  
Jan van Mourik ◽  
Jan Voorberg
Keyword(s):  
Endothelial Cells ◽  
Binding Proteins ◽  
Binding Protein ◽  
Control Release ◽  
Small Gtpase ◽  
Gtp Binding Protein ◽  
Two Dimensional Gel Electrophoresis ◽  
Gtp Binding Proteins ◽  
Dense Granules ◽  
Gtp Binding

SummaryIn endothelial cells von Willebrand factor (vWF) and P-selectin are stored in dense granules, so-called Weibel-Palade bodies. Upon stimulation of endothelial cells with a variety of agents including thrombin, these organelles fuse with the plasma membrane and release their content. Small GTP-binding proteins have been shown to control release from intracellular storage pools in a number of cells. In this study we have investigated whether small GTP-binding proteins are associated with Weibel-Palade bodies. We isolated Weibel-Palade bodies by centrifugation on two consecutive density gradients of Percoll. The dense fraction in which these subcellular organelles were highly enriched, was analysed by SDS-PAGE followed by GTP overlay. A distinct band with an apparent molecular weight of 28,000 was observed. Two-dimensional gel electrophoresis followed by GTP overlay revealed the presence of a single small GTP-binding protein with an isoelectric point of 7.1. A monoclonal antibody directed against RalA showed reactivity with the small GTP-binding protein present in subcellular fractions that contain Weibel-Palade bodies. The small GTPase RalA was previously identified on dense granules of platelets and on synaptic vesicles in nerve terminals. Our observations suggest that RalA serves a role in regulated exocytosis of Weibel-Palade bodies in endothelial cells.

Rap1b Association with the Platelet Cytoskeleton Occurs in the Absence of Glycoproteins IIb/IIIa

1998 ◽  
Vol 79 (04) ◽  
pp. 832-836 ◽  
Author(s):  
Thomas Fischer ◽  
Christina Duffy ◽  
Gilbert White
Keyword(s):  
Molecular Weight ◽  
Divalent Cation ◽  
Binding Proteins ◽  
Binding Protein ◽  
Platelet Membrane ◽  
Low Molecular Weight ◽  
Membrane Glycoproteins ◽  
Gtp Binding Protein ◽  
Gtp Binding Proteins ◽  
Gtp Binding

SummaryPlatelet membrane glycoproteins (GP) IIb/IIIa and rap1b, a 21 kDa GTP binding protein, associate with the triton-insoluble, activation-dependent platelet cytoskeleton with similar rates and divalent cation requirement. To examine the possibility that GPIIb/IIIa was required for rap1b association with the cytoskeleton, experiments were performed to determine if the two proteins were linked under various conditions. Chromatography of lysates from resting platelets on Sephacryl S-300 showed that GPIIb/IIIa and rap1b were well separated and distinct proteins. Immunoprecipitation of GPIIb/IIIa from lysates of resting platelets did not produce rap1b or other low molecular weight GTP binding proteins and immunoprecipitation of rap1b from lysates of resting platelets did not produce GPIIb/IIIa. Finally, rap1b was associated with the activation-dependent cytoskeleton of platelets from a patient with Glanzmann’s thrombasthenia who lacks surface expressed glycoproteins IIb and IIIa. Based on these findings, we conclude that no association between GPIIb/IIIa and rap1b is found in resting platelets and that rap1b association with the activation-dependent cytoskeleton is at least partly independent of GPIIb/IIIa.

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