11 research outputs found

    Regulation of signal transduction by RGS4

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    In the present study, the function and the mechanism of action of RGS4, a member of a family of proteins called Regulators of G protein Signalling (RGS) was investigated. A C-terminal fluorescent tag on RGS4 confirmed that transiently transfected RGS4 was predominantly cytosolic and underwent translocation to the plasma membrane of HEK293T cells following co-expression of Gi1, the 2A-adrenoceptor, or agonist activated 2A-adrenoceptor. This translocation of RGS4 to the plasma membrane was most pronounced with the co-expression of the constitutively active GTPase deficient Gi1 Q204L. High-affinity GTPase experiments indicated that RGS4S30C had enhanced GAP activity towards Go1 compared to wild type RGS4. This approach also demonstrated a simultaneous significant decrease in potency of both adrenaline and UK14304 to increase 2A-arenoceptor-activated high-affinity GTPase activity of Go1 in the presence of RGS4 and a further significant decrease in potency of both ligands in the presence of RGS4S30C. This enhanced GAP activity and observed decrease in agonist potency was also transferable to RGS16, an RGS protein closely related to RGS4. The selectivity of the G subunit was also investigated. The enhanced GAP activity and simultaneous significant decrease in potency of adrenaline and UK14304 to increase 2A-arenoceptor-activated high-affinity GTPase activity of RGS4S30C and RGS16S30C was selective for Go1 over Gi1. RGS4S30K and RGS4S30F also demonstrated higher GAP activity than wild type RGS4 but no consensus side chain could be identified that conferred a specific enhancement or loss of GAP activity. The ability to inhibit intracellular calcium release by an activated 1b-adrenoceptor-G11 fusion protein was used in order to investigate the GAP activity of RGS4N88S, RGS4N128A and RGS4N88S,N128A. All three mutants had ablated GAP activity towards G11 and therefore failed to inhibit intracellular calcium release. A novel role for the RGS insensitive mutation G188S was also observed when despite similar expression, G11 G188S significantly reduced agonist-stimulated [35S]GTPS binding compared to wild type G11. RGS4 represents a novel target for pharmaceutical drug development and the study of its regulation of signal transduction is an important area of investigation. These results highlight specific areas of RGS4 research with great pharmaceutical potential

    Global assessment of marine plastic exposure risk for oceanic birds

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    Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species

    Global assessment of marine plastic exposure risk for oceanic birds

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    Plastic pollution is distributed patchily around the world's oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species.B.L.C., C.H., and A.M. were funded by the Cambridge Conservation Initiative’s Collaborative Fund sponsored by the Prince Albert II of Monaco Foundation. E.J.P. was supported by the Natural Environment Research Council C-CLEAR doctoral training programme (Grant no. NE/S007164/1). We are grateful to all those who assisted with the collection and curation of tracking data. Further details are provided in the Supplementary Acknowledgements. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government.Peer reviewe

    Global assessment of marine plastic exposure risk for oceanic birds

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    Plastic pollution is distributed patchily around the world’s oceans. Likewise, marine organisms that are vulnerable to plastic ingestion or entanglement have uneven distributions. Understanding where wildlife encounters plastic is crucial for targeting research and mitigation. Oceanic seabirds, particularly petrels, frequently ingest plastic, are highly threatened, and cover vast distances during foraging and migration. However, the spatial overlap between petrels and plastics is poorly understood. Here we combine marine plastic density estimates with individual movement data for 7137 birds of 77 petrel species to estimate relative exposure risk. We identify high exposure risk areas in the Mediterranean and Black seas, and the northeast Pacific, northwest Pacific, South Atlantic and southwest Indian oceans. Plastic exposure risk varies greatly among species and populations, and between breeding and non-breeding seasons. Exposure risk is disproportionately high for Threatened species. Outside the Mediterranean and Black seas, exposure risk is highest in the high seas and Exclusive Economic Zones (EEZs) of the USA, Japan, and the UK. Birds generally had higher plastic exposure risk outside the EEZ of the country where they breed. We identify conservation and research priorities, and highlight that international collaboration is key to addressing the impacts of marine plastic on wide-ranging species

    Global assessment of marine plastic exposure risk for oceanic birds

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