Abstract 2575 Convergent evolution and membrane binding behavior of oleate hydratase

Mating in the ciliate, Tetrahymena thermophila, is characterized by membrane fusion and fusion pore formation that set the stage for the exchange of genetic material.These changes membrane structure are preceded by the alteration of lipid composition at the site of membrane fusion.One mechanism by which this lipid composition may be altered is through the function of lipid exchange proteins that act at the interface of the endoplasmic reticulum (ER) and the plasma membrane.But membrane contact sites or ER tubulation that is required for these sites to form, had not been observed in Tetrahymena.Recent work from our lab demonstrated that the ER (visualized using Reticulon-GFP and GFP-KDEL expressing Tetrahymena) is distributed throughout the cytoplasm of mating Tetrahymena.Importantly, this localization includes the perinuclear area and tubular extensions that contact the plasma membrane at membrane fusion sites.Furthermore, treatment with an ER tubulation inhibitor, FLI-06, impairs Tetrahymena mating, suggesting that ER tubulation may be required for this process.Future experiments will focus on characterizing ER tubulation in Reticulon knockout Tetrahymena to observe the effects on ER tubulation and Tetrahymena mating.