The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform
Prasanta K. Subudhi - One of the best experts on this subject based on the ideXlab platform.
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Overexpression of an Adenosine Diphosphate-Ribosylation factor gene from the halophytic grass Spartina alterniflora confers salinity and drought tolerance in transgenic Arabidopsis
Plant Cell Reports, 2014Co-Authors: Ratna Karan, Prasanta K. SubudhiAbstract:Key message Isolation, cloning, and expression characterization of an ARF gene from S. alterniflora , demonstrating its involvement in abiotic stress tolerance . Abstract Adenosine Diphosphate-Ribosylation factors (ARFs) are small guanine nucleotide-binding proteins that play an important role in intracellular protein trafficking necessary for undertaking multiple physiological functions in plant growth and developmental processes. However, little is known about the mechanism of ARF functioning at the molecular level, as well as its involvement in abiotic stress tolerance. In this study, we demonstrated the direct involvement of an ARF gene SaARF from a grass halophyte Spartina alterniflora in abiotic stress adaptation for the first time. SaARF , which encodes a protein with predicted molecular mass of 21 kDa, revealed highest identity with ARF of Oryza sativa. The SaARF gene is transcriptionally regulated by salt, drought, cold, and ABA in the leaves and roots of S. alterniflora. Arabidopsis plants overexpressing SaARF showed improved seed germination and survival of seedlings under salinity stress. Similarly, SaARF transgenic Arabidopsis plants were more tolerant to drought stress, compared to wild-type plants, by maintaining chlorophyll synthesis, increasing osmolyte synthesis, and stabilizing membrane integrity. Oxidative damage due to moisture stress in transgenic Arabidopsis was also reduced possibly by activating antioxidant genes, AtSOD1 and AtCAT . Our results suggest that enhanced drought and salinity tolerance conferred by the SaARF gene may be due to its role in mediating multiple abiotic stress tolerance mechanisms.
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overexpression of an Adenosine Diphosphate Ribosylation factor gene from the halophytic grass spartina alterniflora confers salinity and drought tolerance in transgenic arabidopsis
Plant Cell Reports, 2014Co-Authors: Ratna Karan, Prasanta K. SubudhiAbstract:Key message Isolation, cloning, and expression characterization of an ARF gene fromS. alterniflora, demonstrating its involvement in abiotic stress tolerance.
Ratna Karan - One of the best experts on this subject based on the ideXlab platform.
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Overexpression of an Adenosine Diphosphate-Ribosylation factor gene from the halophytic grass Spartina alterniflora confers salinity and drought tolerance in transgenic Arabidopsis
Plant Cell Reports, 2014Co-Authors: Ratna Karan, Prasanta K. SubudhiAbstract:Key message Isolation, cloning, and expression characterization of an ARF gene from S. alterniflora , demonstrating its involvement in abiotic stress tolerance . Abstract Adenosine Diphosphate-Ribosylation factors (ARFs) are small guanine nucleotide-binding proteins that play an important role in intracellular protein trafficking necessary for undertaking multiple physiological functions in plant growth and developmental processes. However, little is known about the mechanism of ARF functioning at the molecular level, as well as its involvement in abiotic stress tolerance. In this study, we demonstrated the direct involvement of an ARF gene SaARF from a grass halophyte Spartina alterniflora in abiotic stress adaptation for the first time. SaARF , which encodes a protein with predicted molecular mass of 21 kDa, revealed highest identity with ARF of Oryza sativa. The SaARF gene is transcriptionally regulated by salt, drought, cold, and ABA in the leaves and roots of S. alterniflora. Arabidopsis plants overexpressing SaARF showed improved seed germination and survival of seedlings under salinity stress. Similarly, SaARF transgenic Arabidopsis plants were more tolerant to drought stress, compared to wild-type plants, by maintaining chlorophyll synthesis, increasing osmolyte synthesis, and stabilizing membrane integrity. Oxidative damage due to moisture stress in transgenic Arabidopsis was also reduced possibly by activating antioxidant genes, AtSOD1 and AtCAT . Our results suggest that enhanced drought and salinity tolerance conferred by the SaARF gene may be due to its role in mediating multiple abiotic stress tolerance mechanisms.
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overexpression of an Adenosine Diphosphate Ribosylation factor gene from the halophytic grass spartina alterniflora confers salinity and drought tolerance in transgenic arabidopsis
Plant Cell Reports, 2014Co-Authors: Ratna Karan, Prasanta K. SubudhiAbstract:Key message Isolation, cloning, and expression characterization of an ARF gene fromS. alterniflora, demonstrating its involvement in abiotic stress tolerance.
Waldemar Kolanus - One of the best experts on this subject based on the ideXlab platform.
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Guanine nucleotide exchange factors of the cytohesin family and their roles in signal transduction
Immunological Reviews, 2007Co-Authors: Waldemar KolanusAbstract:Members of the cytohesin protein family, a group of guanine nucleotide exchange factors for Adenosine Diphosphate Ribosylation factor (ARF) guanosine triphosphatases, have recently emerged as important regulators of signal transduction in vertebrate and invertebrate biology. These proteins share a modular domain structure, comprising carboxy-terminal membrane recruitment elements, a Sec7 homology effector domain, and an amino-terminal coiled-coil domain that serve as a platform for their integration into larger signaling complexes. Although these proteins have a highly similar overall build, their individual biological functions appear to be at least partly specific. Cytohesin-1 had been identified as a regulator of beta2 integrin inside-out regulation in immune cells and was subsequently shown to be involved in mitogen-associated protein kinase signaling in tumor cell proliferation as well as in T-helper cell activation and differentiation. Cytohesin-3, which had been discovered to be strongly associated with T-cell anergy, was very recently described as an essential component of insulin signal transduction in Drosophila and in human and murine liver cells. Future work will aim to dissect the mechanistic details of the modes of action of the cytohesins as well as to define the precise roles of these versatile proteins in vertebrates at the genetic level.
Michael Famulok - One of the best experts on this subject based on the ideXlab platform.
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A Homogeneous Fluorescence Resonance Energy Transfer System for Monitoring the Activation of a Protein Switch in Real Time
Journal of the American Chemical Society, 2011Co-Authors: Anke Bill, Heike Blockus, Dagmar Stumpfe, Anton Schmitz, Jürgen Bajorath, Michael FamulokAbstract:A homogeneous fluorescence resonance energy transfer (FRET) system for the real-time monitoring of exchange factor-catalyzed activation of a ras-like small GTPase is described. The underlying design is based on supramolecular template effects exerted by protein–protein interactions between the GTPase Adenosine Diphosphate Ribosylation factor (ARF) and its effector protein GGA3. The GTPase is activated when bound to guanosine triphosphate (GTP) and switched off in its guanosine Diphosphate (GDP)-bound state. Both states are accompanied by severe conformational changes that are recognized by GGA3, which only binds the GTPase “on” state. GDP-to-GTP exchange, i.e., GTPase activation, is catalyzed by the guanine nucleotide exchange factor cytohesin-2. When GGA3 and the GTPase ARF1 are labeled with thoroughly selected FRET probes, with simultaneous recording of the fluorescence of an internal tryptophan residue in ARF1, the conformational changes during the activation of the GTPase can be monitored in real time...
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A homogeneous fluorescence resonance energy transfer system for monitoring the activation of a protein switch in real time
Journal of the American Chemical Society, 2011Co-Authors: Anke Bill, Heike Blockus, Dagmar Stumpfe, Anton Schmitz, Jürgen Bajorath, Michael FamulokAbstract:A homogeneous fluorescence resonance energy transfer (FRET) system for the real-time monitoring of exchange factor-catalyzed activation of a ras-like small GTPase is described. The underlying design is based on supramolecular template effects exerted by protein?protein interactions between the GTPase Adenosine Diphosphate Ribosylation factor (ARF) and its effector protein GGA3. The GTPase is activated when bound to guanosine triphosphate (GTP) and switched off in its guanosine Diphosphate (GDP)-bound state. Both states are accompanied by severe conformational changes that are recognized by GGA3, which only binds the GTPase ?on? state. GDP-to-GTP exchange, i.e., GTPase activation, is catalyzed by the guanine nucleotide exchange factor cytohesin-2. When GGA3 and the GTPase ARF1 are labeled with thoroughly selected FRET probes, with simultaneous recording of the fluorescence of an internal tryptophan residue in ARF1, the conformational changes during the activation of the GTPase can be monitored in real time. We applied the FRET system to a multiplex format that allows the simultaneous identification and distinction of small-molecule inhibitors that interfere with the cytohesin-catalyzed ARF1 activation and/or with the interaction between activated ARF1-GTP and GGA3. By screening a library of potential cytohesin inhibitors, predicted by in silico modeling, we identified new inhibitors for the cytohesin-catalyzed GDP/GTP exchange on ARF1 and verified their increased potency in a cell proliferation assay.
James W Hamilton - One of the best experts on this subject based on the ideXlab platform.
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parathyroid hormone pth secretion stimulation of pth secretion by a peptide derived from the Adenosine Diphosphate Ribosylation factor
Endocrinology, 1994Co-Authors: L Newman, Betty M Drees, L Forte, James W HamiltonAbstract:Using preparations of dispersed bovine parathyroid cells, we have investigated the effect of a 16-residue synthetic peptide, ARF-16, which corresponds to the N-terminus of the ADP-Ribosylation factor, on the secretion of PTH. We find it to be a very effective secretagogue for PTH secretion, acting in a dose- and time-dependent manner. At concentrations in the range of 15-25 microM, the ARF peptide stimulated PTH secretion to a greater degree than low extracellular calcium, and at 25 microM was more effective than isoproterenol. The stimulatory effect of ARF was not dependent on the extracellular calcium concentration over the range of 0.5-3 mM. Upon testing other synthetic peptides of similar size we found no effect on PTH secretion, indicating that the ARF-16 effect is specific. In an attempt to define the structural elements of ARF that are required for activity, we tested several analogs of ARF with amino acids deleted from the N- and C-terminus. Deletion of the 2 N-terminal residues yielded a peptide ...
