Location: Plant Physiology and Genetics ResearchTitle: Deciphering the mechanisms for targeting and interaction of Arabidopsis Lipid Droplet Associated Protein (LDAP) to the lipid droplet surface) Author
Submitted to: International Symposium on Plant Lipids
Publication Type: Abstract Only
Publication Acceptance Date: 7/2/2013
Publication Date: 8/1/2013
Citation: Gidda, S.K., Park, S., Watt, S., Yurchenko, O., Andrews, D.W., Chapman, K.D., Mullen, R.T., Dyer, J.M. 2013. Deciphering the mechanisms for targeting and interaction of Arabidopsis Lipid Droplet Associated Protein (LDAP) to the lipid droplet surface. International Symposium on Plant Lipids. Vol.162 pp.1926-1936. Interpretive Summary:
Technical Abstract: We recently identified a new class of lipid-droplet associated proteins (LDAPs) in plants that share extensive sequence similarity with abundant structural proteins that coat rubber particles in rubber-producing plants. A majority of higher plants, however, including those that do not produce rubber, contain three LDAP-like genes, suggesting a broader role in lipid droplet biogenesis. Here we show that all three isoforms of Arabidopsis LDAP do indeed target to the surface of lipid droplets in plant cells and when overexpressed cause conspicuous alterations in the morphology of lipid droplets and their intracellular distribution. To gain a better understanding of how LDAPs target specifically to lipid droplets, we performed a series of experiments on the LDAP encoded by At3g05500, which is expressed predominantly in developing seeds. Through a combination of mutagenesis experiments, protein-protein interaction analyses, and in vitro liposome-binding assays, we show that the targeting of LDAPs is determined in part by cis-acting information within the protein, weak but significant protein-lipid interactions, and potential oligomerization on the lipid droplet surface. Screening of an Arabidopsis cDNA library using At3g05500 as bait revealed additional heteromeric protein-binding partners that may be involved in LDAP targeting and/or activity. The identity of these proteins, as well as implications for lipid droplet biogenesis and function, will be discussed.