UDP-glucose pyrophosphorylase. An old protein with new tricks.

Sugars are central to a plant’s raison d’etre as products of photosynthesis. They are the ultimate source of energy and carbon skeletons for all biomolecules, and they provide the material out of which a plant builds its cell walls, fibers, and wood. Thus, regulation of any activity involved in biosynthesis of sugars, especially Suc (the major transport form of carbon in plants), is of utmost interest in understanding the growth and development strategies of a plant. Sugars are also potent regulators of gene expression, via e.g. a hexokinase (HXK) transduction mechanism that senses hexoses, or via Suc-specific or osmoticum transduction pathways, further underlying the importance of sugars in plant homeostasis.