Life on Earth is sustained by plants. Growth and development in the plant kingdom is mediated by the controlled distribution of sugars and the hormone auxin, but we still know surprisingly little about the molecular details of this essential part of fundamental plant metabolism. MUM-GROW will elucidate the molecular mechanism of sugar and auxin transmembrane transport in plants. It moves the frontiers of the field by shifting the focus to molecular studies in vitro allowing structural and biochemical experiments to be performed.<br/><br/>Correct plant growth and development is completely dependent on sugar uptake in growth zones (the meristem), and made possible in all plants by sugar transporters called SUCs and STPs. Growth polarity is created by an asymmetrical gradient of auxin mediated by auxin transporters called PINs. Despite extensive research, the molecular mechanisms of SUC, STP and PIN transport remains unknown. If we knew the molecular determinants of their function, it would allow us to predict, augment and possibly modify plant responses to a changing environment.<br/><br/>I will address this using a complementary set of methods founded in structural biology to determine the 3-dimensional structures of key players in these transmembrane transport systems. This will be combined with biochemical characterization to address important mechanistic questions and elucidate their molecular mechanism.<br/><br/>Understanding the mechanisms that govern plasticity in growth is essential for determining resilience of whole ecosystems. This proposal will lead to a breakthrough in our understanding of sugar and auxin homeostasis, a fundamental part of basic plant metabolism. It has tremendous potential for the societal challenge to secure sufficient food for our global population in a sustainable balance between environmental impact and resource exploitation. Furthermore, this proposal will uncover general molecular principles of transmembrane uptake and export pertaining to all organisms.