RESEARCH PROFILE

Phospholipids are essential for the construction of eukaryotic cell membranes, which play a fundamental role in compartmentalising the biochemistry of life. The quantity and composition of phospholipids are tightly regulated during growth and development, and in response to environmental change, so that membranes always maintain their structure and function.

Research in mammals and yeast (Saccharomyces cerevisiae) has uncovered elegant metabolite signaling mechanisms, both transcriptional and post-translational, that allow the cell to sense changes in key lipid intermediates and adjust phospholipid synthesis (and turnover) accordingly. Analogous mechanisms are also likely to exist in plants but surprisingly they have not been elucidated. Because phospholipids are essential, genetic analysis of their regulation through loss-of-function is problematic. However, we have recently isolated an Arabidopsis thaliana double mutant in two phosphatidate phosphatases (pah1 pah2) that produces approximately twice as much phospholipid in its leaves as wild type plants. To our knowledge this is the first plant mutant to over-produce phospholipids and the gain-of-function phenotype provides a unique tool.

The objective of this project is to use the pah1 pah2 mutant (and corresponding genes) to discover how phospholipid biosynthesis is regulated in Arabidopsis and how it is coordinated with a core developmental process, the cell cycle. This discovery will be of fundamental scientific interest, particularly as there is already evidence to show that many key elements of the regulatory mechanism(s) in plants must differ from those described in mammals or yeast.

Christian works in the Plant Lipid Metabolism Group studying the Regulation of plant phospholipid biosynthesis

BACKGROUND

PhD in Molecular Cell Biology: "Functional analysis of vacuolar sorting receptor (VSR) genes in Arabidopsis thaliana", University of Warwick.

SELECTED PUBLICATIONS

• Tolley N, Sparkes IA, Hunter PR, Craddock CP, Nuttall J, Roberts LM, Hawes C, Pedrazzini E, Frigerio L. (2008) 'Overexpression of a plant reticulon remodels the lumen of the cortical endoplasmic reticulum but does not perturb protein transport.' Traffic 9 94 - 102 (1398-9219)
• Craddock CP, Hunter PR, Szakacs E, Hinz G, Robinson DG, Frigerio L. (2008) 'Lack of a vacuolar sorting receptor leads to non-specific missorting of soluble vacuolar proteins in Arabidopsis seeds.' Traffic 9 416 - 418 (1398-9219)
• Hunter PR, Craddock CP, Di Benedetto S, Roberts LM, Frigerio L., , (2007) 'Fluorescent reporter proteins for the tonoplast and the vacuolar lumen identify a single vacuolar compartment in Arabidopsis cells.' Plant Physiology 145 1371 - 1382 (0032-0889)
• Jolliffe NA, Craddock CP, Frigerio L. (2005) 'Pathways for protein transport to seed storage vacuoles.' Biochemical Society Transactions 33 1016 - 1018 (0300-5127)

Further Publications