The Roles of Guanine Nucleotide Binding Proteins in Health and Disease

G-proteins are important mediators of cellular and tissue functions and are characterised by a recognition site for Guanine Triphosphate (GTP), Guanine Diphosphate (GDP) and possess intrinsic GTPase activity. They play important roles in signal transduction responsible for cytoskeletal remodelling, cellular differentiation and vesicular transport. They are made up of three types namely, the small G-proteins, the sensors and the heterotrimeric G-proteins. The G-protein heterotrimers consist of G-alpha (G), G-beta (G$) and G-gamma (G() subunits. Each heterotrimeric G-protein have different subunits and the combination of these subunits define the specific role of each G-protein. The activation of G subunits regulates the activity of effector enzymes and ion channels while G$( subunits function in the regulation of mitogen-activated protein kinase (MAP-kinase) pathway. The G-protein-mediated signal transduction is important in the regulation of a cells morphological and physiological response to external stimuli. MAPKs are involved in the phosphorylation of transcription factors that stimulate gene transcription. Gs stimulates adenylate cyclase, thereby increasing cyclic adenosine monophosphate (cAMP) leading to the phosphorylation and subsequent activation of Ca_+ channels. G proteins are involved in disease pathology through several mechanisms which interfere with the G protein activity. Other disease pathologies associated with abnormal mutations in G proteins can interfere with signal transduction pathways which may involve signal transmission that is either excessive, by augmentation of G protein function, or insufficient, via inactivation of G proteins.sch_dieBenians, A., M. Nobles, S. Hosny and A. Tinker, 2005. Regulators of G-protein signalling form a quaternary complex with the agonist, receptor, and G-protein. 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The Importance of Consistent Global Forest Aboveground Biomass Product Validation

Several upcoming satellite missions have core science requirements to produce data for accurate forest aboveground biomass mapping. Largely because of these mission datasets, the number of available biomass products is expected to greatly increase over the coming decade. Despite the recognized importance of biomass mapping for a wide range of science, policy and management applications, there remains no community accepted standard for satellite-based biomass map validation. The Committee on Earth Observing Satellites (CEOS) is developing a protocol to fill this need in advance of the next generation of biomass-relevant satellites, and this paper presents a review of biomass validation practices from a CEOS perspective. We outline the wide range of anticipated user requirements for product accuracy assessment and provide recommendations for the validation of biomass products. These recommendations include the collection of new, high-quality in situ data and the use of airborne lidar biomass maps as tools toward transparent multi-resolution validation. Adoption of community-vetted validation standards and practices will facilitate the uptake of the next generation of biomass products

Export promotion in the Czech Republic: can it help?

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