Trends in Plant Science
ReviewInositol signaling and plant growth
Section snippets
Inositol phospholipids as regulators of growth
Most plant responses to external stimuli involve a change in growth and therefore membrane biogenesis. Membrane trafficking and signaling are inexorably linked in regulating cellular metabolism and controlling growth. To coordinate these processes, evolution appears to have capitalized on the stereospecificity of the PIs. During membrane trafficking, individual inositol phospholipids on the vesicle surface specify functional information like cogs on a wheel. As vesicles traffic from the
Ins(1,4,5)P3: a means of coordinating growth
The microdomains of PtdIns(4,5)P2 localized throughout the membranes establish a network of initiation sites for generating rapid, transient increases in Ins(1,4,5)P3 in response to stimuli. Although the sequence of events leading up to stimulus-mediated Ins(1,4,5)P3 production has not been delineated in plants, any stimulus that increases cytosolic Ca2+ in a PtdIns(4,5)P2 microdomain should, in theory, activate plant PLCs to produce a transient increase in Ins(1,4,5)P3 (Ref. 2). It is not
What does the future hold?
As we begin to combine biochemical and molecular genetic approaches to understand physiological responses on a macro scale it will be important to characterize the changes in inositol signaling as plants mature and respond to changes in nutrient flux and environmental conditions36. Crucial to interpreting these data will be an understanding of the subcellular localization of the proteins and lipids. To this end, the recent development of useful tools such as the fluorescently labeled inositol
Acknowledgements
We apologize to the authors who could not be cited because of limited reference space. We would like to acknowledge the support of the National Science Foundation (MCB-9604285), the National Aeronautics and Space Administration (NAGW-4984) and the North Carolina Agriculture Research Service to W.F.B., and a DAAD fellowship HSPIII financed by the German Federal Ministry of Education, Science, Research and Technology to I.H. We also acknowledge Bjørn Drøbak, Steve C. Huber, Gloria K. Muday and
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