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

scholarly journals Formation of a functional ribosome-membrane junction during translocation requires the participation of a GTP-binding protein.

1986 ◽  
Vol 103 (6) ◽  
pp. 2253-2261 ◽  
Author(s):  
T Connolly ◽  
R Gilmore
Keyword(s):  
Signal Sequence ◽  
Binding Protein ◽  
Signal Recognition Particle ◽  
Secretory Protein ◽  
Signal Recognition ◽  
Gtp Binding Protein ◽  
Gtp Binding ◽  
Protease Digestion ◽  
Nascent Chain

The requirement for ribonucleotides and ribonucleotide hydrolysis was examined at several distinct points during translocation of a secretory protein across the endoplasmic reticulum. We monitored binding of in vitro-assembled polysomes to microsomal membranes after removal of ATP and GTP. Ribonucleotides were not required for the initial low salt-insensitive attachment of the ribosome to the membrane. However, without ribonucleotides the nascent secretory chains were sensitive to protease digestion and were readily extracted from the membrane with either EDTA or 0.5 M KOAc. In contrast, nascent chains resisted extraction with either EDTA or 0.5 M KOAc and were insensitive to protease digestion after addition of GTP or nonhydrolyzable GTP analogues. Translocation of the nascent secretory polypeptide was detected only when ribosome binding was conducted in the presence of GTP. Thus, translocation-competent binding of the ribosome to the membrane requires the participation of a novel GTP-binding protein in addition to the signal recognition particle and the signal recognition particle receptor. The second event we examined was translocation and processing of a truncated secretory polypeptide. Membrane-bound polysomes bearing an 86-residue nascent chain were generated by translation of a truncated preprolactin mRNA. Ribonucleotide-independent translocation of the polypeptide was detected by cleavage of the 30-residue signal sequence after puromycin termination. Nascent chain transport, per se, is apparently dependent upon neither ribonucleotide hydrolysis nor continued elongation of the polypeptide once a functional ribosome-membrane junction has been established.

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

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

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.

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.

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