Peter H. Quail UC Berkeley/ARS Plant Gene Expression Center, Albany CA 94710, USA Peter Quail is Professor of Plant and Microbial Biology, University of California, Berkeley, and Research Director, of the ARS/UCB Plant Gene Expression Center, Albany, California.
Professor Quail is a recipient of the American Society of Photobiologists Research Award, the LI-COR Award for Distinguished Contributions to Photochemistry/Photobiology, Corresponding Membership of the Australian Society of Plant Physiologists, recipient of ISI award for top 15 most highly cited authors in the Plant & Animal Science discipline, Fellow of the American Association for the Advancement of Science, recipient of the Stephen Hales Award from the American Society of Plant Biologists and a Member of the U.S. National Academy of Sciences. His research is focused on defining the molecular mechanism by which the phytochrome (phy) family of plant sensory photoreceptors controls gene expression, and thereby plant growth and development, in response to informational light-signals from the environment. His laboratory has provided evidence that the signaling mechanism involves rapid, direct, intranuclear interaction of the light-activated photoreceptor molecule with a sub-family of basic helix-loop-helix (bHLH) transcription factors (called PIFs), with resultant induction of phosphorylation and polyubiqitination of the PIF proteins, as a prelude to degradation of the bHLH factors by the ubiquitin-proteasome system, and consequent genome-wide gene-expression changes. His research program has identified the protein kinases and E3 ubiquitin ligases involved and the genome-wide gene-set that are direct targets of transcriptional regulation by the PIFs.
Our research interests are in defining the mechanisms by which light signals are perceived and transduced by the phytochrome (phy)-PIF module to Direct-Target Genes (DTGs), focused specifically on the two sequential interfaces (a) between the phy and PIF proteins, and (b) between the PIFs and their DTGs. Existing data suggest that these components engage in dynamic multimolecular complexes comprised variously of (a) protein kinases (that include PPKs (Photoregulatory Protein Kinases)) and E3 ubiquitin ligases (including LRBs, EBFs and COP1-SPA), that sequentially phosphorylate and ubiquitinate the PIFs to regulate their abundance, and (b) a diversity of other interacting components that modulate the intrinsic transcriptional activation activity of the PIFs (including the core clock protein, TOC1). The data suggest yet greater complexity in the system, including potential mechanistic differences among the individual PIFs, as yet unidentified factors that may contribute to the signaling process, and trans-factors that may modulate PIF transcriptional regulatory capacity in situ at the genome interface, independently of the level of promoter occupancy. Our current efforts, using a combination of mass-spectrometric, biochemical and molecular genetic approaches to explore these possibilities will be described.