1 The brown adipocyte protein CIDEA promotes lipid droplet 2 fusion via a phosphatidic acid-binding amphipathic helix 3 David Barneda1, Joan Planas-Iglesias2, Maria L. Gaspar3, Dariush Mohammadyani4, 4 Sunil Prasannan2, Dirk Dormann5, Gil-Soo Han5, Stephen A. Jesch3, George M. 5 Carman6, Valerian Kagan4, Malcolm G. Parker1, Nicholas T. Ktistakis7, Judith Klein- 6 Seetharaman2, 4, Ann M. Dixon8, Susan A. Henry3, Mark Christian1,2*. 7 1 Institute of Reproductive and Developmental Biology, Imperial College London, London W12 ONN, 8 UK 9 2 Warwick Medical School, University of Warwick, Coventry, CV4 7AL, UK. 10 3 Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York 14853, USA. 11 4 Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA. 12 5 Microscopy Facility, MRC Clinical Sciences Centre, Imperial College London, London W12 0NN, UK 13 6 Department of Food Science, Rutgers Center for Lipid Research, Rutgers University, New Brunswick, 14 New Jersey 08901, USA. 15 7 Signalling Programme, Babraham Institute, Cambridge CB22 3AT, UK. 16 8 Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK. 17 18 19 *Corresponding author. 20 E-mail:
[email protected] 21 Phone number: 44 2476 96 8585 1 22 23 Summary 24 Maintenance of energy homeostasis depends on the highly regulated storage and 25 release of triacylglycerol primarily in adipose tissue and excessive storage is a feature of 26 common metabolic disorders. CIDEA is a lipid droplet (LD)-protein enriched in brown 27 adipocytes promoting the enlargement of LDs which are dynamic, ubiquitous organelles 28 specialized for storing neutral lipids.