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Plants have to endure adverse environmental conditions, among them, drought and salinity constrain agricultural productivity most dramatically. Many of the plant adaptive responses take place at cell membrane where it is required the regulation o a variety of ion channels and transporters. This adjusts the intracellular ion concentration necessary for cell live. From a molecular point of view, the levels of abscisic acid (ABA) and calcium encode the information to orchestrate cell response to stress. We have discovered and characterized a new family of proteins, CAR for C2-domain ABA-related, that target ABA recognition machinery to the cell membrane. The joined structural and biochemical analyses has provided a working model that illustrates how CAR proteins anchor to plasma membrane and specifically bind the ABA receptors. As the activity of these proteins is dependent of calcium, they represent a central hub decoding ABA and calcium stimuli and provide a target for biotechnological work for the use of plants in our benefit.
C2-Domain Abscisic Acid-Related Proteins Mediate the Interaction of PYR/PYL/RCAR Abscisic Acid Receptors with the Plasma Membrane and Regulate Abscisic Acid Sensitivity in Arabidopsis
L. Rodriguez, M. Gonzalez-Guzmán, M. Díaz, A. Rodrigues, A.C. Izquierdo-Garcia, M. Peirats-Llobet, R. Antonia, D. Fernández, J.A. Márquez, J.M. Mulet, A. Albert and P.L. Rodríguez
The Plant Cell (2014) Advanced Online Publication (doi:10.1105/tpc.114.129973)
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In collaboration with a group led by the CNIO and the CRG, the IQFR has participated in a study to understand the interactions that regulate the dynamic properties of microtubules and their organization during mitosis. The work has focused on the characterization of the molecular interaction between TACC3 and chTOG. These proteins are key in forming the internal cellular framework that enables and sustains cell division. The work was carried out by a multiexperimental approximation using a variety of biophysical (SAXS, NMR, CD), biochemical and cellular techniques. It has been possible to define the minimum active domain of TACC3 and derive a 3D model by SAXS. By NMR we have identified key residues for molecular interaction. From these data, designed mutants have allowed us to see, in cells, how preventing this association the mitotic spindle assembly is not produced.
The results may help to optimise current oncological therapies specifically designed to fight against this framework, named by the scientific community as microtubules
This study was funded by the CONSOLIDER programme of the Ministry of Economy and Competitiveness, the Ramón Areces Foundation, and the Community of Madrid.
XTACC3-XMAP215 association reveals an asymmetric interaction promoting microtubule elongation.
Mortuza GB, Cavazza T, Garcia-Mayoral MF, Hermida D, Peset I, Pedrero JG, Merino N, Blanco FJ, Lyngsø J, Bruix M, Pedersen JS, Vernos I, Montoya G. Nat Commun. 2014 Sep 29;5:5072. doi: 10.1038/ncomms6072.
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The transport of ions through the plant cell membrane establishes the key physicochemical parameters for cell function. Stress situations such as those created by soil salinity or low potassium conditions alter the ion transport across the membrane producing dramatic changes in the cell turgor, the membrane potential, and the intracellular pH and concentrations of toxic cations such as sodium and lithium. As a consequence, fundamental metabolic routes are inhibited.
The CIPK family of twenty-six protein kinases regulates the function of several ion transporters at the cell membrane to restore ion homeostasis under stress situations. Our analyses provide an explanation on how the CIPKs are differentially activated to coordinate the adequate cell response to a particular stress.
Proceedings of the National Academy of Sciences, PNAS (2014), (doi:10.1073/pnas.1407610111)http://www.pnas.org/content/early/2014/10/02/1407610111
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The IQFR will participate in one of the next Mars rover instruments, the Mars Environmental Dynamics Analyzer (MEDA), a set of sensors that will provide measurements of temperature, wind speed and direction, pressure, relative humidity and dust size and shape. The principal investigator is Jose' Antonio Rodriguez-Manfredi, Centro de Astrobiologia, Instituto Nacional de Tecnica Aeroespacial, Spain, and the team of Alfonso Sáiz of the IQFR will participate in the ozone sensor.
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The evolution of nitrogen dioxide (NO2) over Spain from 1996 to 2012 has been analyzed by a group of scientists led by the Atmospheric Chemistry and Climate Group (AC2) at IQFR (CSIC), with the participation of the University of Bremen, the University of Castilla-La Mancha (UCLM) and the National Institute for Aerospace Technology (INTA).
The study is focused ondensely populated cities of Barcelona, Bilbao, Madrid, Sevilla and Valencia, employing 17 years of NO2 measurements, from 1996 to 2012. This data series combines observations from in-situ air quality monitoring networks and the satellite-based instruments GOME and SCIAMACHY. The results in these five cities show a smooth decrease in the NO2 concentrations of 2% per year in the period 1996-2008, due to the implementation of emissions control environmental legislation, and a more abrupt descend of ~7% per year from 2008 to 2012 as a consequence of the economic recession. In the whole Spanish territory the NO2 levels have decreased by ~22% from 1996 to 2012. In some cities, e.g. Madrid, the decrease in NO2 concentrations surpasses 40%. Statistical analysis of several economic indicators is used to investigate the different factors driving the NO2 concentration trends over Spain during the last two decades.
The work has been published in Scientific Reports
C.A. Cuevas, A. Notario, J.A. Adame, A. Hilboll, A. Richter, J.P. Burrows and A. Saiz-Lopez. Sci. Rep 4, 5887; DOI:10.1038/srep05887 (2014).
Averaged tropospheric NO2 vertical column density for 1996 (left) and 2011 (right)
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Many dynamical processes in molecules occur in extraordinarily short timescales, of the order of femtoseconds (1 fs = 10-15 s). In order to follow these processes in real time it is necessary to use the fastest stopwatches available, which are made of ultrashort laser light pulses. In the Center for Ultrashort Lasers (CLUR), in the Complutense University, Madrid, a research team with the participation of Rebeca de Nalda, from IQFR (CSIC), has been taking snapshots of some of these ultrafast processes in molecular systems, while trying to understand the details of the underlying light-matter interaction phenomena.
The new ingredient that has been recently added to these studies is an additional laser pulse that goes beyond the observation of the reaction, and is capable of modifying its course. This pulse is sufficiently intense to alter the molecular potentials, and thus, it causes changes in the products of the reaction and the speeds they acquire in reactions where bonds are broken. This work has been published in Nature Chemistry, and it is a demonstration that the fine control of the properties of this "control" laser pulse turns it into a true "photonic scalpel" capable of manipulating chemical reactions, as well as shedding new light into the dynamics of complex molecular dynamical processes.
M. E. Corrales, J. González-Vázquez, G. Balerdi, I. R. Solá, R. de Nalda, L. Bañares, Control of ultrafast molecular photodissociation by laser field induced potentials, Nature Chemistry (2014), doi:10.1038/nchem.2006
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Separation of daughter cells during bacterial cell division requires that the septal cross wall be split by peptidoglycan hydrolases. In Streptococcus pneumoniae an essential protein termed PcsB is predicted to perform this critical operation. Recent evidence shows that the activity of PcsB is regulated by the transmembrane FtsEX complex. In this work the muralytic activity of PcsB is demonstrated for the first time. Furthermore, we report the crystal structure of full-length PcsB showing an unprecedented dimeric structure in which the unique V-shaped coiled-coil domain of each monomer acts as a molecular tweezers locking down the catalytic domain of its dimeric partner in an inactive configuration. This finding strongly suggests that the release of the catalytic domains requires an ATP-driven conformational change in the FtsEX complex, which is most likely conveyed towards the catalytic domains through a set of coordinated movements of the α-helices forming the coiled-coil domain of PcsB.
Sergio G. Bartual, Daniel Straume, Gro Anita Stamsås, Inés G. Muñoz, Carlos Alfonso, Martín Martínez-Ripoll, Leiv Sigve Håvarstein* & Juan A. Hermoso *
Structural basis of PcsB-mediated cell separation in Streptococcus pneumoniae
Nature Communications (2014). DOI: 10.1038/ncomms4842
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"Pablo García-Risueño started his work on this subject when doing his PhD at the institute."
The problem of the electrostatic potential is almost ubiquituous in chemical and atomic/molecular simulations. In this paper just published at the Journal of Computational Chemistry (and appearing at its front cover), Pablo García-Risueno et al. present an analysis of different methods to calculate the classical electrostatic Hartree potential created by charge distributions. This work may enable more accurate and efficient simulations, helping scientists to tackle many new systems.
