Fig. 1. SNX9 has a functional BAR domain and induces massive membrane tubulation. (A) Multiple sequence alignment of the BAR domains in SNX9 and other proteins with Clustal X. Conserved residues are highlighted with the following color code: yellow, hydrophobic; green, polar; blue, basic; red, acidic. Secondary structure of rAmphiphysin2 was determined from the crystal structure and that of SNX9 was predicted using online program NPS@ (http://npsa-pbil.ibcp.fr). (B) COS-7 cells were transfected with GFP-SNX9 and time-lapse imaging was performed 20 hours after transfection. Images were captured every 5 seconds for 5 minutes. High-magnification views are of the regions enclosed in rectangles. Arrowheads indicate the ends of tubules that underwent elongation. Scale bars: 30 µm (low magnification) and 3 µm (high magnification). (C) Domain structures of SNX9 and its deletion mutants. Tubulation ability is indicated. (D) COS-7 cells were transfected with GFP-tagged SNX9 or SNX9-SH3 and tubule formation and cellular localization were observed. Scale bars: 30 µm.