1. Dobro et al. (2013) Molecular Biology of the Cell, 24, 2319-2327. 50nm Archaeal Tetraether Liposomes Parkson L. Chong, Temple University, DMR 1105277 Electron cryotomography (ECT) of CdvA-coated PLFE liposomes (A-C) Top, middle, and bottom slices through a 3- D cryotomogram of a CdvA-coated PLFE liposome. (D) 3-D segmentation, showing CdvA filaments (blue) wrapping around the PLFE liposome (purple). Archaeal bipolar tetraether lipids (BTL) are appealing biomaterials that hold great promise for technological applications. We focused on liposomes composed of the polar lipid fraction E (PLFE), which is one of the main BTL isolated from the thermoacidophilic archaeon Sulfolobus acidocaldarius. In this archaeon, BTL are the dominating lipid species (~90%). It was found recently (see left) that CdvA forms alpha-helical filaments on PLFE liposomes. CdvA is a protein in archaea that recruits the protein ESCRT-III to the membrane. ESCRT-III drives membrane division. Our previous negative stain electron microscopy study revealed extensive deformation of PLFE liposomes in the presence of both CdvA and ESCRT-III but not with individual proteins. ( see left, Scale bar = 100 nm ) Conclusion: PLFE liposomes alone are extremely stable; however, they can be easily deformed by CdvA plus ESCRT-III proteins. Samson et al. (2011) Molecular Cell 41, 186-196

2. Archaeal Tetraether Liposomes Parkson L. Chong, Temple University, DMR 1105277 Training undergraduate and graduate students ● This project was used to train several undergraduate students (including two from the minority groups) and two Ph.D. graduate students in this funding period. ● One of the undergraduate students (Ellah Hur) is a co-author of the paper published in Archaea (doi:10.1155/2012/138439) and two undergraduate students (Jacqueline Rivera and Oxana Placinta) were co-authored in posters presented at the annual Biophysical Society meeting in Philadelphia, PA, in February 2013. ● This project supported one summer intern through the collaboration with the Temple University Undergraduate Research program. ● The two graduate students presented posters at the Biophysical Society meeting as well as at Dawn Marks Research Day and the translational medicine symposium at Temple University. Broader Impacts on Science and Technology Archaeal BTL liposomes alone are known to be extraordinarily stable against a number of physical and chemical stressors such as autoclaving, elevated pressure and temperature, detergents, oxidation, fusogenic compounds, etc. Thus, BTL liposomes are appealing biomaterials that hold great promise for technological applications such as being a more durable lipid matrix for biosensing and a more stable drug carrier for targeted therapy. We now know that archaeal BTL liposomes can be disintegrated by using just two proteins (CdvA and ESCRT –III), with CdvA binding on membrane surface as the initial step of the liposome deformation (see previous slide). The new data suggest that in addition to technological applications mentioned above, BTL liposomes can be used as an excellent model system for basic research on archaea cell division or membrane budding.