Prof. Sima Lev’ team showed that the Nir2 protein mainly localizes to the Golgi in interphase cells, and isolated the integral ER-membrane protein VAP-B as Nir2-interacting protein. They showed that Nir2-VAP-B interaction is mediated by the FFAT (EFFDAxE) motif within the N-terminal region of Nir2. The ‘FFAT’ (two phenylalanines, ‘FF’, in acidic tract) motif was identified in 17 distinct eukaryotic proteins, of which 14 are directly implicated in lipid binding or lipid sensing, including the homologs of oxysterol-binding protein (OSBP), the homologs of Goodpasture’s antigen-binding protein (GPBP), the three Nir proteins, which Prof. Sima Lev identified, and Opi1p, a transcriptional regulator of phospholipid synthesis in yeast.
