FIGURE 8.

Amphiphilic α-helix mediates membrane association of the N-terminal region of BASIC. A, representation of the N-terminal sequences of rBASIC, rBASIC ΔN15–25, and rBASIC^R21P; the putative α-helix is labeled with asterisks. B, representative images of GFP fused to the N-terminal sequences of rBASIC or GFP alone in HEK293 cells (green, left panel). The plasma membrane was stained using CellMask^TM deep red plasma stain (red, middle panel). Right panel, merged images. Scale bars, 5 μm. C, representative Western blot showing the exclusive presence of the full N-terminal domain in the insoluble membrane fraction (lower panel), whereas the N-terminal domain lacking amino acids 15–25 and the N-terminal domain containing the R21P mutation are exclusively present in the cytosolic soluble fraction (upper panel). Loading control, tubulin (middle panel).