An exploration of mechanisms for Arabidopsis TCP transcription factor activity at an interface of development and immunity

2018 ◽  
Author(s):  
◽  
Benjamin J. Spears

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] "The work presented in this dissertation aimed to characterize new functions and regulatory targets for TCP8, potentially in both defense and development signaling networks. Using in vitro and in vivo promoter interaction screens in yeast and Arabidopsis, respectively, the PTI-related immune receptor gene EFR as well as a set of growth-related BR signaling genes were identified as regulatory targets of TCP8; these findings were verified through direct interaction assays characterization of tcp mutants for associated phenotypes. Additionally, SRFR1-interacting TCPs were shown to be post-translationally modified by SUMO proteins, alongside data suggesting that SRFR1 sequence motifs that facilitate interactions with SUMO are critical to its function. Together, these data describe novel roles for TCP8 and other class I TCPs, as well as novel regulatory mechanisms for their activities in the context of their interactions with SRFR1 and other TPR proteins. As a highly-conserved TF family among plants, including economically relevant crop species, advancing our understanding of TCP regulatory activities could eventually yield translational benefits to agriculture and food production worldwide."--Page 36-37.

Cells ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 2390
Author(s):  
Ankush Borlepawar ◽  
Nesrin Schmiedel ◽  
Matthias Eden ◽  
Lynn Christen ◽  
Alexandra Rosskopf ◽  
...  

Dysbindin, a schizophrenia susceptibility marker and an essential constituent of BLOC-1 (biogenesis of lysosome-related organelles complex-1), has recently been associated with cardiomyocyte hypertrophy through the activation of Myozap-RhoA-mediated SRF signaling. We employed sandy mice (Dtnbp1_KO), which completely lack Dysbindin protein because of a spontaneous deletion of introns 5–7 of the Dtnbp1 gene, for pathophysiological characterization of the heart. Unlike in vitro, the loss-of-function of Dysbindin did not attenuate cardiac hypertrophy, either in response to transverse aortic constriction stress or upon phenylephrine treatment. Interestingly, however, the levels of hypertrophy-inducing interaction partner Myozap as well as the BLOC-1 partners of Dysbindin like Muted and Pallidin were dramatically reduced in Dtnbp1_KO mouse hearts. Taken together, our data suggest that Dysbindin’s role in cardiomyocyte hypertrophy is redundant in vivo, yet essential to maintain the stability of its direct interaction partners like Myozap, Pallidin and Muted.


1998 ◽  
Vol 18 (6) ◽  
pp. 3395-3404 ◽  
Author(s):  
Ching-Hung Shen ◽  
Janet Stavnezer

ABSTRACT Signal transducer and activator of transcription 6 (Stat6) and NF-κB are widely distributed transcription factors which are induced by different stimuli and bind to distinct DNA sequence motifs. Interleukin-4 (IL-4), which activates Stat6, synergizes with activators of NF-κB to induce IL-4-responsive genes, but the molecular mechanism of this synergy is poorly understood. Using glutathioneS-transferase pulldown assays and coimmunoprecipitation techniques, we find that NF-κB and tyrosine-phosphorylated Stat6 can directly bind each other in vitro and in vivo. An IL-4-inducible reporter gene containing both cognate binding sites in the promoter is synergistically activated in the presence of IL-4 when Stat6 and NF-κB proteins are coexpressed in human embryonic kidney 293 (HEK 293) cells. The same IL-4-inducible reporter gene is also synergistically activated by the endogenous Stat6 and NF-κB proteins in IL-4-stimulated I.29μ B lymphoma cells. Furthermore, Stat6 and NF-κB bind cooperatively to a DNA probe containing both sites, and the presence of a complex formed by their cooperative binding correlates with the synergistic activation of the promoter by Stat6 and NF-κB. We conclude that the direct interaction between Stat6 and NF-κB may provide a basis for synergistic activation of transcription by IL-4 and activators of NF-κB.


2018 ◽  
Author(s):  
◽  
Ashutosh Shripad Phadte

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Cataractogenesis in the eye lens occurs as a result of protein aggregation. Of the multiple mutations in [alpha]A-crystallins associated with the development of congenital hereditary cataract, three identified mutations target R21 within the N- terminal domain of the protein. On structural and functional characterization of a recently identified mutant of [alpha]A-crystallin, [alpha]A-R21Q, we revealed the contribution of R21 in dictating the interaction of [alpha]A-crystallin with other proteins. [alpha]A-R21Q showed and enhanced chaperone-like function, and increased binding to lens fiber cell membranes. Transduction of mutant proteins in ARPE-19 cells prevented their apoptosis in the presence of oxidative stress, suggesting a role for R21 in modulating the anti-apoptotic function of [alpha]A-crystallin. In addition, the R21Q point mutation rescued the chaperone-like activity of [alpha]A-G98R crystallin as well as palliated [alpha]A-G98R mediated cytotoxicity otherwise observed in transduction experiments. Although another mutation, R157Q rescued the chaperone-like activity of [alpha]A-G98R, the double mutant exhibited a loss of its cytoprotective function. The results therefore implicate an important role of R21 in regulating the functional aspect of [alpha]A-crystallin. [alpha]A-crystallin derived peptides have been shown to prevent non-specific aggregation of unfolding proteins in vitro. We show that the [alpha]A-crystallin derived mini-chaperone (mini-[alpha]A) mediated stabilization of self-aggregating [alpha]A-G98R crystallin and bovine [subscript]-crystallin occurs via compensation of lost surface charge. The observation therefore suggests a plausible mechanism of action of [alpha]A-crystallin derived peptides of therapeutic interest.


2018 ◽  
Author(s):  
◽  
Ashutosh S. Phadte

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Cataractogenesis in the eye lens occurs as a result of protein aggregation. Of the multiple mutations in [alpha]A-crystallins associated with the development of congenital hereditary cataract, three identified mutations target R21 within the N-terminal domain of the protein. On structural and functional characterization of a recently identified mutant of [alpha]A-crystallin, [alpha]A-R21Q, we revealed the contribution of R21 in dictating the interaction of [alpha]A-crystallin with other proteins. [Alpha]A-R21Q showed and enhanced chaperone-like function, and increased binding to lens fiber cell membranes. Transduction of mutant proteins in ARPE-19 cells prevented their apoptosis in the presence of oxidative stress, suggesting a role for R21 in modulating the anti-apoptotic function of [alpha]A-crystallin. In addition, the R21Q point mutation rescued the chaperone-like activity of [alpha]A-G98R crystallin as well as palliated [alpha]A-G98R mediated cytotoxicity otherwise observed in transduction experiments. Although another mutation, R157Q rescued the chaperone-like activity of [alpha]A-G98R, the double mutant exhibited a loss of its cytoprotective function. The results therefore implicate an important role of R21 in regulating the functional aspect of [alpha]A-crystallin. [Alpha]A-crystallin derived peptides have been shown to prevent non-specific aggregation of unfolding proteins in vitro. We show that the [alpha]A-crystallin derived mini-chaperone (mini-[alpha]A) mediated stabilization of self-aggregating [alpha]A-G98R crystallin and bovine [gamma]-crystallin occurs via compensation of lost surface charge. The observation therefore suggests a plausible mechanism of action of [alpha]A-crystallin derived peptides of therapeutic interest.


1992 ◽  
Vol 67 (06) ◽  
pp. 660-664 ◽  
Author(s):  
Virgilio Evangelista ◽  
Paola Piccardoni ◽  
Giovanni de Gaetano ◽  
Chiara Cerletti

SummaryDefibrotide is a polydeoxyribonucleotide with antithrombotic effects in experimental animal models. Most of the actions of this drug have been observed in in vivo test models but no effects have been reported in in vitro systems. In this paper we demonstrate that defibrotide interferes with polymorphonuclear leukocyte-induced human platelet activation in vitro. This effect was not related to any direct interaction with polymorphonuclear leukocytes or platelets, but was due to the inhibition of cathepsin G, the main biochemical mediator of this cell-cell cooperation. Since cathepsin G not only induces platelet activation but also affects some endothelial cell functions, the anticathepsin G activity of defibrotide could help to explain the antithrombotic effect of this drug.


2019 ◽  
Author(s):  
Priya Prakash ◽  
Travis Lantz ◽  
Krupal P. Jethava ◽  
Gaurav Chopra

Amyloid plaques found in the brains of Alzheimer’s disease (AD) patients primarily consists of amyloid beta 1-42 (Ab42). Commercially, Ab42 is synthetized using peptide synthesizers. We describe a robust methodology for expression of recombinant human Ab(M1-42) in Rosetta(DE3)pLysS and BL21(DE3)pLysS competent E. coli with refined and rapid analytical purification techniques. The peptide is isolated and purified from the transformed cells using an optimized set-up for reverse-phase HPLC protocol, using commonly available C18 columns, yielding high amounts of peptide (~15-20 mg per 1 L culture) in a short time. The recombinant Ab(M1-42) forms characteristic aggregates similar to synthetic Ab42 aggregates as verified by western blots and atomic force microscopy to warrant future biological use. Our rapid, refined, and robust technique to purify human Ab(M1-42) can be used to synthesize chemical probes for several downstream in vitro and in vivo assays to facilitate AD research.


Carbon ◽  
2016 ◽  
Vol 103 ◽  
pp. 291-298 ◽  
Author(s):  
Valeria Ettorre ◽  
Patrizia De Marco ◽  
Susi Zara ◽  
Vittoria Perrotti ◽  
Antonio Scarano ◽  
...  

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