共查询到20条相似文献,搜索用时 31 毫秒
1.
GRAB proteins,novel members of the NAC domain family,isolated by their interaction with a geminivirus protein 总被引:27,自引:0,他引:27
Xie Qi Sanz-Burgos Andrés P. Guo Huishan García Juan Antonio Gutiérrez Crisanto 《Plant molecular biology》1999,39(4):647-656
Geminiviruses encode a few proteins and depend on cellular factors to complete their replicative cycle. As a way to understand geminivirus-host interactions, we have searched for cellular proteins which interact with viral proteins. By using the yeast two-hybrid technology and the wheat dwarf geminivirus (WDV) RepA protein as a bait, we have isolated a family of proteins which we termed GRAB (for Geminivirus Rep A-binding). We report here the molecular characterization of two members, GRAB1 and GRAB2. We have found that the 37 C-terminal amino acids of RepA are required for interaction with GRAB proteins. This region contains residues conserved in an equivalent region of the RepA proteins encoded by other viruses of the WDV subgroup. The N-terminal domain of GRAB proteins is necessary and sufficient to interact with WDV RepA. GRAB proteins contain an unique acidic C-terminal domain while their N-terminal domain, of ca. 170 amino acids, are highly conserved in all of them. Interestingly, this conserved N-terminal domain of GRAB proteins exhibits a significant amino acid homology to the NAC domain present in proteins involved in plant development and senescence. GRAB1 and GRAB2 mRNAs are present in cultured cells and roots but are barely detectable in leaves. GRAB expression inhibits WDV DNA replication in cultured wheat cells. Our studies highlight the importance that the pathway(s) mediated by GRAB proteins, as well as by other NAC domain-containing proteins, might have on geminivirus DNA replication in connection to plant growth, development and senescence pathways. 相似文献
2.
3.
In the molecular interplay between pathogenic microorganisms and their host, proteolytic mechanisms are believed to play a crucial role. Here we find that the important human pathogen Streptococcus pyogenes (group A Streptococcus) expresses a surface protein with high affinity (Ka = 2.0 x 10(8) M-1) for alpha2-macroglobulin (alpha2M), the dominating proteinase inhibitor of human plasma. The immunoglobulin-binding protein G of group C and G streptococci also contains an alpha2M-binding domain and a gene encoding protein GRAB (protein G-related alpha2M-binding protein) was identified in the S. pyogenes Genome Sequencing data base. The grab gene is present in most S. pyogenes strains and is well conserved. Protein GRAB has typical features of a surface-attached protein of Gram-positive bacteria. It also contains a region homologous to parts of the alpha2M-binding domain of protein G and a variable number of a unique 28-amino acid-long repeat. Using Escherichia coli-produced protein GRAB and synthetic GRAB peptides, the alpha2M-binding region was mapped to the NH2-terminal part of protein GRAB, which is the region with homology to protein G. An isogenic S. pyogenes mutant lacking surface-associated protein GRAB showed no alpha2M binding activity and was attenuated in virulence when injected intraperitoneally in mice. Finally, alpha2M bound to the bacterial surface via protein GRAB was found to entrap and inhibit the activity of both S. pyogenes and host proteinases, thereby protecting important virulence determinants from proteolytic degradation. This regulation of proteolytic activity at the bacterial surface should affect the host-microbe relation during S. pyogenes infections. 相似文献
4.
Zygogramma bicolorata Pallister (Coleoptera: Chrysomelidae) is an effective biocontrol agent of Parthenium hysterophorus L. which is an alien invasive herbaceous weed with a pan-tropical distribution. The present study aimed to assess the effects of temperature and altitude on feeding attributes (consumption rate, conversion efficiency and growth rate) of adults from the wild populations of Z. bicolorata inhabiting India and Nepal. Results revealed that adults inhabiting areas of low temperature (24°C ‒ 25°C) and high altitude (415 m ‒1400 m) were large and had higher food consumption rates. In contrast, those inhabiting areas of high temperature (34°C ‒ 36°C) and low altitude (81 m ‒ 229 m) were smaller and had higher food utilization efficiencies. In all the eco-climatic regions, females were larger than males and had higher feeding attributes than their counterparts. Temperature between 27°C and 30°C was found optimal for Z. bicolorata adults to convert and utilize the food biomass to body mass. Above the optimal temperature the feeding attributes decreased. Present results suggest that there exists a possibility for decrease in body size, and thereby weed biocontrol efficiency of Z. bicolorata adults with an increase in temperature due to global climate change. 相似文献
5.
Lorenzo Albertazzi Barbara Storti Marco Brondi Sebastian Sulis Sato Gian Michele Ratto Giovanni Signore Fabio Beltram 《Journal of visualized experiments : JoVE》2013,(79)
The development of fluorescent indicators represented a revolution for life sciences. Genetically encoded and synthetic fluorophores with sensing abilities allowed the visualization of biologically relevant species with high spatial and temporal resolution. Synthetic dyes are of particular interest thanks to their high tunability and the wide range of measureable analytes. However, these molecules suffer several limitations related to small molecule behavior (poor solubility, difficulties in targeting, often no ratiometric imaging allowed). In this work we introduce the development of dendrimer-based sensors and present a procedure for pH measurement in vitro, in living cells and in vivo. We choose dendrimers as ideal platform for our sensors for their many desirable properties (monodispersity, tunable properties, multivalency) that made them a widely used scaffold for several biomedical devices. The conjugation of fluorescent pH indicators to the dendrimer scaffold led to an enhancement of their sensing performances. In particular dendrimers exhibit reduced cell leakage, improved intracellular targeting and allow ratiometric measurements. These novel sensors were successfully employed to measure pH in living HeLa cells and in vivo in mouse brain. 相似文献
6.
Conor P. Horgan Sara R. Hanscom Mary W. McCaffrey 《Biochemical and biophysical research communications》2013
Co-ordination of Rab GTPase function has emerged as a crucial mechanism in the control of intracellular trafficking processes in eukaryotic cells. Here, we show that GRAB/Rab3IL1 [guanine nucleotide exchange factor for Rab3A; RAB3A interacting protein (rabin3)-like 1], a protein that has previously be shown to act as a GEF (guanine nucleotide exchange factor) for Rab3a, Rab8a and Rab8b, is also a binding partner for Rab11a and Rab11b, but not the closely related Rab25 GTPase. We demonstrate that exogenous expression of Rab11a and Rab11b shift GRAB’s distribution from the cytoplasm onto membranes. We find that the Rab11a/Rab11b-binding region of GRAB lies within its carboxy-terminus, a region distinct from its GEF domain and Rab3a-binding region. Finally, we describe a GRAB deletion mutant (GRABΔ223–228) that is deficient in Rab11-binding ability. These data identify GRAB as a dual Rab-binding protein that could potentially link Rab3 and Rab11 and/or Rab8 and Rab11-mediated intracellular trafficking processes. 相似文献
7.
The refractive index resolution of a surface plasmon resonance (SPR) sensor has been significantly improved these years; however, higher sensing performance is always desired. In this work, we propose a line-monitoring, long-range SPR sensor whose resolution is much better than conventional SPR sensors. Also, in contrast to mono-channel detection, multichannel detection, using line-monitoring technique, can detect multiple channels concurrently. In this way, this system achieves a refractive index resolution of 4.0?×?10??7 refractive index units and can monitor multiple molecular interactions simultaneously. Finally, a model experiment detecting the Escherichia coli bacteria has demonstrated the potential for biomedical applications of this system. 相似文献
8.
9.
《Endocrine practice》2021,27(8):790-797
ObjectiveMany patients with type 2 diabetes treated with premixed insulin gradually have inadequate glycemic control and switch to a basal-bolus regimen, which raises some concerns for weight gain and increased hypoglycemic risk. Switching to combination use of glp-1 agonist and basal insulin may be an alternative option.MethodsAfter a 12-week premixed human insulin 70/30 dosage optimization period, 200 patients with HbA1c of 7.0% to 10.0% were randomized into 24-week treatment groups with exenatide twice a day plus glargine or with aspart 70/30 twice a day.ResultsAfter 24 weeks, the patients receiving exenatide plus glargine (n = 90) had improved HbA1c control compared with those receiving aspart 70/30 (n = 90) (least squares mean change: ‒0.59 vs ‒0.13%; difference [95% CI]: ‒0.45 [‒0.74 to ‒0.17]) in the full analysis set population. Weight decreased 3.5 kg with exenatide and decreased 0.4 kg with aspart 70/30 (P < .001). The insulin dose was reduced 10.7 units/day (95% CI, ‒12.2 to ‒9.2 units; P < .001) with exenatide, and increased 9.7 units/day (95% CI, 8.2 to 11.2 units; P < .001) with aspart 70/30. The most common adverse events were gastrointestinal adverse effects in the exenatide group (nausea [21%], vomiting [16%], diarrhea [13%]). The incidence of hypoglycemia was similar in 2 groups (27% for exenatide and 38% for aspart 70/30; P = .1).ConclusionIn premixed human insulin‒treated patients with type 2 diabetes with inadequate glycemic control, switching to exenatide twice a day plus glargine was superior to aspart 70/30 twice a day for glycemic and weight control. 相似文献
10.
Visualization of single molecules and specific subsets of cells is widely used for studies of biological processes and particularly in immunological research. Recent technological advances have provided a qualitative change in biological visualization from studying of ??snapshot?? pictures to real-time continuous observation of cellular dynamics in vivo. Contemporary methods of in vivo imaging make it possible to localize specific cells within organs and tissues, to study their differentiation, migration, and cell-to-cell interactions, and to follow some intracellular events. Fluorescence intravital microscopy plays an especially important role in high resolution molecular imaging. The methods of intravital microscopy are quickly advancing thanks to improvements in molecular sensors, labeling strategies, and detection approaches. Novel techniques allow simultaneous detection of various probes with better resolution and depth of imaging. In this review, we describe current methods for in vivo imaging, with special accent on fluorescence approaches, and discuss their applications for medical and biological studies. 相似文献
11.
Georg Greiner Utz Dornberger Inge Paegelow Bernward A. Schlkens Claus Liebmann Siegmund Reissmann 《Journal of peptide science》1998,4(2):92-100
Continuing the studies on structural requirements of bradykinin antagonists, it has been found that analogues with dehydrophenylalanine (ΔPhe) or its ring‒substituted analogues (ΔPhe(X)) at position 5 act as antagonists on guinea pig pulmonary artery, and on guinea pig ileum. Because both organs are considered to be bradykinin B2receptor tissues, the analogues with ΔPhe or ΔPhe(X) at position 5, but without any replacement at position 7, seem to represent a new structural type of B2receptor antagonist. All the analogues investigated act as partial antagonists; they inhibit the bradykinin‒induced contraction at low concentrations and act as agonists at higher concentrations. Ring substitutions by methyl groups or iodine reduce both the agonistic and antagonistic activity. Only substitution by fluorine gives a high potency. Incorporation of ΔPhe into different representative antagonists with key modifications at position 7 does not enhance the antagonist activity of the basic structures, with one exception. Only the combination of ΔPhe at position 5 with D Phe at position 7 increases the antagonistic potency on guinea pig ileum by about one order of magnitude. Radio‒ligand binding studies indicate the importance of position 5 for the discrimination of B2receptor subtypes. The binding affinity to the low‒affinity binding site (KL) was not significantly changed by replacement of Phe by ΔPhe. In contrast, ring‒methylation of ΔPhe results in clearly reduced binding to KL. The affinity to the high‒affinity binding site (KH) was almost unchanged by the replacement of Phe in position 5 by ΔPhe, whereas the analogue with 2‒methyl‒dehydrophenylalanine completely failed to detect the KH‒site. The peptides were synthesized on the Wang‒resin according to the Fmoc/Butstrategy using Mtr protection for the side chain of Arg. The dehydrophenylalanine analogues were prepared by a strategy involving PyBop couplings of the dipeptide unit Fmoc‒Gly‒ΔPhe(X)‒OH to resin‒bound fragments. © 1998 European Peptide Society and John Wiley & Sons, Ltd. 相似文献
12.
Luo HR Saiardi A Nagata E Ye K Yu H Jung TS Luo X Jain S Sawa A Snyder SH 《Neuron》2001,31(3):439-451
Diphosphoinositol-pentakisphosphate (InsP7) and bis-diphosphoinositol tetrakisphosphate (InsP8) possess pyrophosphate bonds. InsP7 is formed from inositol hexakisphosphate (InsP6) by recently identified InsP6 kinases designated InsP6K1 and InsP6K2. We now report the identification, cloning, and characterization of a novel protein, GRAB (guanine nucleotide exchange factor for Rab3A), which interacts with both InsP6K1 and Rab3A, a Ras-like GTPase that regulates synaptic vesicle exocytosis. GRAB is a physiologic GEF (guanine nucleotide exchange factor) for Rab3A. Consistent with a role of Rab3A in synaptic vesicle exocytosis, GRAB regulates depolarization-induced release of dopamine from PC12 cells and nicotinic agonist-induced hGH release from bovine adrenal chromaffin cells. The association of InsP6K1 with GRAB fits with a role for InsP7 in vesicle exocytosis. 相似文献
13.
Claire B. Otara Christopher E. Jones Nadine D. Younan John H. Viles Maurice R. Elphick 《Biochimica et Biophysica Acta - Proteins and Proteomics》2014,1844(2):358-365
The neuropeptides S1 (GFNSALMFamide) and S2 (SGPYSFNSGLTFamide), which share sequence similarity, were discovered in the starfish Asterias rubens and are prototypical members of the SALMFamide family of neuropeptides in echinoderms. SALMFamide neuropeptides act as muscle relaxants and both S1 and S2 cause relaxation of cardiac stomach and tube foot preparations in vitro but S2 is an order of magnitude more potent than S1. Here we investigated a structural basis for this difference in potency using spectroscopic techniques. Circular dichroism spectroscopy showed that S1 does not have a defined structure in aqueous solution and this was supported by 2D nuclear magnetic resonance experiments. In contrast, we found that S2 has a well-defined conformation in aqueous solution. However, the conformation of S2 was concentration dependent, with increasing concentration inducing a transition from an unstructured to a structured conformation. Interestingly, this property of S2 was not observed in an N-terminally truncated analogue of S2 (short S2 or SS2; SFNSGLTFamide). Collectively, the data obtained indicate that the N-terminal region of S2 facilitates peptide self-association at high concentrations, which may have relevance to the biosynthesis and/or bioactivity of S2 in vivo. 相似文献
14.
The GTPase Arf1p and the ER to Golgi cargo receptor Erv14p cooperate to recruit the golgin Rud3p to the cis-Golgi
下载免费PDF全文
![点击此处可从《The Journal of cell biology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Rud3p is a coiled-coil protein of the yeast cis-Golgi. We find that Rud3p is localized to the Golgi via a COOH-terminal domain that is distantly related to the GRIP domain that recruits several coiled-coil proteins to the trans-Golgi by binding the small Arf-like GTPase Arl1p. In contrast, Rud3p binds to the GTPase Arf1p via this COOH-terminal "GRIP-related Arf-binding" (GRAB) domain. Deletion of RUD3 is lethal in the absence of the Golgi GTPase Ypt6p, and a screen of other mutants showing a similar genetic interaction revealed that Golgi targeting of Rud3p also requires Erv14p, a cargo receptor that cycles between the endoplasmic reticulum and Golgi. The one human protein with a GRAB domain, GMAP-210 (CEV14/Trip11/Trip230), is known to be on the cis-Golgi, but the COOH-terminal region that contains the GRAB domain has been reported to bind to centrosomes and gamma-tubulin (Rios, R.M, A. Sanchis, A.M. Tassin, C. Fedriani, and M. Bornens. 2004. Cell. 118:323-335). In contrast, we find that this region binds to the Golgi in a GRAB domain-dependent manner, suggesting that GMAP-210 may not link the Golgi to gamma-tubulin and centrosomes. 相似文献
15.
16.
R. Melarange D. J. Potton M. C. Thorndyke M. R. Elphick 《Proceedings. Biological sciences / The Royal Society》1999,266(1430):1785
Feeding in starfish of the species Asterias rubens involves eversion of the cardiac stomach over prey such as mussels and oysters. For eversion to be accomplished the cardiac stomach must be relaxed. Here we show that two neuropeptides (S1 and S2) belonging to a family of echinoderm neuropeptides called SALMFamides cause concentration-dependent relaxation of the cardiac stomach in vitro, with S2 being 10 to 20 times more potent than S1. Previously, we have obtained evidence that nitric oxide mediates neural control of cardiac stomach relaxation in Asterias. However, S2-induced relaxation of the cardiac stomach is not affected by an inhibitor of the nitric oxide ''receptor'' soluble guanylyl cyclase. Therefore, cardiac stomach relaxation in starfish appears to be controlled by at least two neural signalling pathways acting in parallel. To assess the involvement of the SALMFamides in mediating cardiac stomach eversion in Asterias, experiments were performed in which water (control) or S1 or S2 was injected into the perivisceral coelom. Cardiac stomach eversion was observed after 5 min in 3% of tests with water, in 11% of tests with S1 and in 57% of tests with S2. Importantly, the effectiveness of S1 and S2 in promoting eversion corresponds with their relative potency as cardiac stomach relaxants in vitro. Collectively, these data indicate that SALMFamide neuropeptides may be involved in regulating the process of cardiac stomach eversion in starfish. 相似文献
17.
18.
Adhiraj Roy Salman Hashmi Zerui Li Angela D. Dement Kyu Hong Cho Jeong-Ho Kim 《Molecular biology of the cell》2016,27(5):862-871
Methylglyoxal (MG) is a cytotoxic by-product of glycolysis. MG has inhibitory effect on the growth of cells ranging from microorganisms to higher eukaryotes, but its molecular targets are largely unknown. The yeast cell-surface glucose sensors Rgt2 and Snf3 function as glucose receptors that sense extracellular glucose and generate a signal for induction of expression of genes encoding glucose transporters (HXTs). Here we provide evidence that these glucose sensors are primary targets of MG in yeast. MG inhibits the growth of glucose-fermenting yeast cells by inducing endocytosis and degradation of the glucose sensors. However, the glucose sensors with mutations at their putative ubiquitin-acceptor lysine residues are resistant to MG-induced degradation. These results suggest that the glucose sensors are inactivated through ubiquitin-mediated endocytosis and degraded in the presence of MG. In addition, the inhibitory effect of MG on the glucose sensors is greatly enhanced in cells lacking Glo1, a key component of the MG detoxification system. Thus the stability of these glucose sensors seems to be critically regulated by intracellular MG levels. Taken together, these findings suggest that MG attenuates glycolysis by promoting degradation of the cell-surface glucose sensors and thus identify MG as a potential glycolytic inhibitor. 相似文献
19.