A structural model for K2P potassium channels based on 23 pairs of interacting sites and continuum electrostatics

K2PØ, the two-pore domain potassium background channel that determines cardiac rhythm in Drosophila melanogaster, and its homologues that establish excitable membrane activity in mammals are of unknown structure. K2P subunits have two pore domains flanked by transmembrane (TM) spans: TM1-P1-TM2-TM3-P2-TM4. To establish spatial relationships in K2PØ, we identified pairs of sites that display electrostatic compensation. Channels silenced by the addition of a charge in pore loop 1 (P1) or P2 were restored to function by countercharges at specific second sites. A three-dimensional homology model was determined using the crystal structure of KV1.2, effects of K2PØ mutations to establish alignment, and compensatory charge–charge pairs. The model was refined and validated by continuum electrostatic free energy calculations and covalent linkage of introduced cysteines. K2P channels use two subunits arranged so that the P1 and P2 loops contribute to one pore, identical P loops face each other diagonally across the pore, and the channel complex has bilateral symmetry with a fourfold symmetric selectivity filter

The Landscape Services of Ecology

Connectivity is critical to maintaining ecological functions and benefits in human-modified landscapes, including urban areas. However, the literature on this topic has been limited by inconsistent terminology and methods, and largely omits human access to nature and its benefits as a form of connectivity. We build upon previous theory to present four distinct but interrelated categories of connectivity (habitat, geophysical, eco-social, and landscape) and use the Ecosystem Services framework to review the socio-ecological benefits which depend on them. There are also many overlaps, conflicts, and synergies among connectivity categories and their associated services and disservices. Identifying the services which arise from these four categories of connectivity, and how they interact, can help to maximize the benefits of connectivity, improve understanding of complex socio-ecological systems across disciplines, and develop more holistic decision-making processes. ***NOTE*** This presentation should precede Carole Hardy et al., A framework for incorporating ecosystem connectivity into urban planning for livable cities . We would also like these two topics to be considered for a lunchtime breakout discussion

Ecosystem Connectivity for Livable Cities: a Connectivity Benefits Framework for Urban Planning

Urbanization disrupts landscapes and ecosystem functions, which poses threats to biodiversity, social systems, and human health, particularly among vulnerable populations. Urban land-use planners are faced with competing demands for housing, safety, transportation, and economic development and often lack tools to integrate these with protecting environmental functions. We identify three major barriers to integrating the benefits that flow with connected, functioning ecosystems into land-use planning. The lack of a shared language among planners and stakeholders poses a barrier to the restoration and preservation of ecological features. Methods of incorporating the benefits from connectivity are not standardized because values are not readily available or lack credibility. Ecological restoration tends to be poorly coordinated at broad scales, and thus often fails to achieve landscape-level objectives. To address these challenges, we developed a novel integrated framework, the Connectivity Benefits Framework (CBF), which combines the benefits from three categories of ecosystem connectivity with benefit- and risk-relevant indicators, enabling both monetary and non-monetary valuation of benefits. Moreover, it provides a method to identify and visualize the multiple and overlapping benefits from management actions to aid in prioritizing initiatives that support ecosystem functions. Unlike software tools that incorporate generalized values of ecosystem services at a landscape level, the CBF guides a systematic approach to community-engaged land-use planning that prioritizes localized societal needs while protecting biodiversity and ecosystem function for more equitable, resilient cities. We demonstrate the potential for multiple overlapping benefits from actions that restore and protect ecosystem connectivity by applying the framework to a transit planning project in Portland, Oregon

Habitat, Geophysical, and Eco-Social Connectivity: Benefits of Resilient Socio-Ecological Landscapes

Context Connections among ecosystems and their components are critical to maintaining ecological functions and benefits in human-modified landscapes, including urban areas. However, the literature on connectivity and ecosystem services has been limited by inconsistent terminology and methods, and largely omits human access to nature and its benefits as a form of connectivity. Objectives In this paper, we build upon previous research and theory to define distinct categories of connectivity, considering both ecological and social dimensions, and identify ecosystem services that are supported by them. Methods We reviewed the literature to determine socio–ecological benefits that depend on the categories of connectivity. Results We identified four distinct but interrelated categories of connectivity: landscape, habitat, geophysical, and eco-social connectivity. Each connectivity category directly or indirectly supports many ecosystem services. There are overlaps, conflicts, and synergies among connectivity categories and their associated services and disservices. Conclusions Identifying the services that arise from these four categories of connectivity, and how they interact, can help build a common understanding of the value of connectivity to maximize its benefits, improve understanding of complex socio–ecological systems across disciplines, and develop more holistic, socially equitable decision-making processes, especially in urban landscapes