Letter to the Editor: 1 H, 15 N and 13 C chemical shift assignments of the Pleckstrin Homology domain of the Human Protein Kinase B (PKB/Akt)

International audienc

Fungal X-Intrinsic Protein Aquaporin from Trichoderma atroviride: Structural and Functional Considerations

The major intrinsic protein (MIP) superfamily is a key part of the fungal transmembrane transport network. It facilitates the transport of water and low molecular weight solutes across biomembranes. The fungal uncharacterized X-Intrinsic Protein (XIP) subfamily includes the full protein diversity of MIP. Their biological functions still remain fully hypothetical. The aim of this study is still to deepen the diversity and the structure of the XIP subfamily in light of the MIP counterparts-the aquaporins (AQPs) and aquaglyceroporins (AQGPs)-and to describe for the first time their function in the development, biomass accumulation, and mycoparasitic aptitudes of the fungal bioagent Trichoderma atroviride. The fungus-XIP Glade, with one member (TriatXIP), is one of the three clades of MIPs that make up the diversity of T. atroviride MIPs, along with the AQPs (three members) and the AQGPs (three members). TriatXIP resembles those of strict aquaporins, predicting water diffusion and possibly other small polar solutes due to particularly wider ar/R constriction with a Lysine substitution at the LE2 position. The XIP loss of function in Delta TriatXIP mutants slightly delays biomass accumulation but does not impact mycoparasitic activities. Delta TriatMIP forms colonies similar to wild type; however, the hyphae are slightly thinner and colonies produce rare chlamydospores in PDA and specific media, most of which are relatively small and exhibit abnormal morphologies. To better understand the molecular causes of these deviant phenotypes, a wide-metabolic survey of the ATriatXIPs demonstrates that the delayed growth kinetic, correlated to a decrease in respiration rate, is caused by perturbations in the pentose phosphate pathway. Furthermore, the null expression of the XIP gene strongly impacts the expression of four expressed MIP-encoding genes of T. atroviride, a plausible compensating effect which safeguards the physiological integrity and life cycle of the fungus. This paper offers an overview of the fungal XIP family in the biocontrol agent T. atroviride which will be useful for further functional analysis of this particular MIP subfamily in vegetative growth and the environmental stress response in fungi. Ultimately, these findings have implications for the ecophysiology of Trichoderma spp. in natural, agronomic, and industrial systems

L' intéraction des proto-oncogènes de la famille des Tcl1 avec la protéine Kinase B (Eclairage structurel et dynamique)

MONTPELLIER-BU Sciences (341722106) / SudocSudocFranceF

Cortisol Interaction with Aquaporin-2 Modulates Its Water Permeability: Perspectives for Non-Genomic Effects of Corticosteroids

International audienceAquaporins (AQPs) are water channels widely distributed in living organisms and involved in many pathophysiologies as well as in cell volume regulations (CVR). In the present study, based on the structural homology existing between mineralocorticoid receptors (MRs), glucocorticoid receptors (GRs), cholesterol consensus motif (CCM) and the extra-cellular vestibules of AQPs, we investigated the binding of corticosteroids on the AQP family through in silico molecular dynamics simulations of AQP2 interactions with cortisol. We propose, for the first time, a putative AQPs corticosteroid binding site (ACBS) and discussed its conservation through structural alignment. Corticosteroids can mediate non-genomic effects; nonetheless, the transduction pathways involved are still misunderstood. Moreover, a growing body of evidence is pointing toward the existence of a novel membrane receptor mediating part of these rapid corticosteroids' effects. Our results suggest that the naturally produced glucocorticoid cortisol inhibits channel water permeability. Based on these results, we propose a detailed description of a putative underlying molecular mechanism. In this process, we also bring new insights on the regulatory function of AQPs extra-cellular loops and on the role of ions in tuning the water permeability. Altogether, this work brings new insights into the non-genomic effects of corticosteroids through the proposition of AQPs as the membrane receptor of this family of regulatory molecules. This original result is the starting point for future investigations to define more in-depth and in vivo the validity of this functional model

A Complete Automatic Test Set Generator for Embedded Reactive Systems: From AUTSEG V1 to AUTSEG V2

International audienceOne of the biggest challenges in hardware and software design is to ensure that a system is error-free. Small defects in reactive embedded systems can have disastrous and costly consequences for a project. Preventing such errors by identifying the most probable cases of erratic system behavior is quite challenging. Indeed, tests performed in industry are non-exhaustive, while state space analysis using formal verification in scientific research is inappropriate for large complex systems. We present in this context a new approach for generating exhaustive test sets that combines the underlying principles of the industrial testing technique with the academic-based formal verification. Our method consists in building a generic model of the system under test according to the synchronous approach. The goal is to identify the optimal preconditions for restricting the state space of the model such that test generation can take place on significant subspaces only. So, all the possible test sets are generated from the extracted subspace preconditions. Our approach exhibits a simpler and efficient quasi-flattening algorithm compared with existing techniques, and a useful compiled internal description to check security properties while minimizing the state space combinatorial explosion problem. It also provides a symbolic processing technique for numeric data that provides an expressive and concrete test of the system, while improving system verification (Determinism, Death sequences) and identifying all possible test cases. We have implemented our approach on a tool called AUTSEG V2. This testing tool is an extension of the first version AUTSEG V1 to integrate data manipulations. We present in this paper a complete description of our automatic testing approach including all features presented in AUTSEG V1 and AUTSEG V2

Cortisol Interaction with Aquaporin-2 Modulates Its Water Permeability: Perspectives for Non-Genomic Effects of Corticosteroids

Aquaporins (AQPs) are water channels widely distributed in living organisms and involved in many pathophysiologies as well as in cell volume regulations (CVR). In the present study, based on the structural homology existing between mineralocorticoid receptors (MRs), glucocorticoid receptors (GRs), cholesterol consensus motif (CCM) and the extra-cellular vestibules of AQPs, we investigated the binding of corticosteroids on the AQP family through in silico molecular dynamics simulations of AQP2 interactions with cortisol. We propose, for the first time, a putative AQPs corticosteroid binding site (ACBS) and discussed its conservation through structural alignment. Corticosteroids can mediate non-genomic effects; nonetheless, the transduction pathways involved are still misunderstood. Moreover, a growing body of evidence is pointing toward the existence of a novel membrane receptor mediating part of these rapid corticosteroids’ effects. Our results suggest that the naturally produced glucocorticoid cortisol inhibits channel water permeability. Based on these results, we propose a detailed description of a putative underlying molecular mechanism. In this process, we also bring new insights on the regulatory function of AQPs extra-cellular loops and on the role of ions in tuning the water permeability. Altogether, this work brings new insights into the non-genomic effects of corticosteroids through the proposition of AQPs as the membrane receptor of this family of regulatory molecules. This original result is the starting point for future investigations to define more in-depth and in vivo the validity of this functional model

Hypertrophic cardiomyopathy disease results from disparate impairments of cardiac myosin function and auto-inhibition

Hypertrophic cardiomyopathy (HCM) is caused by point mutations in sarcomeric proteins. Here the authors develop an optimized model of the sequestered state of cardiac myosin and define the features affecting the lever arm compliance, allowing them to group mutations in classes and to elucidate the molecular mechanisms leading to cardiac dysfunction in HCM