FIGURE 4.

NC mutant interferes with SEPT2 Δ15 filament formation. A, FLAG- SEPT2 Δ15 was cotransfected with full-length GFP-SEPT2 (first row), GFP-SEPT2 Δ15 (second row), GFP-G mutant (third row), and GFP-NC mutant (last row) in HeLa cells. Scale bar indicates 10 μm. B, GFP-WT, NC mutant, or G mutant were immunoprecipitated (IP) with GFP antibody and immunoblotted with FLAG antibody to detect FLAG- SEPT2 ΔN15. An asterisk denotes nonspecific bands. The nonspecific band is present in the immunoprecipitated lanes but not in the input lanes. Because this band runs at the same molecular weight as IgG, cross-reactivity of secondary antibodies is likely. UT denotes untransfected control lane. C, schematic depicting the effects of the SEPT2 mutants when coexpressed with SEPT2 Δ15 filaments. Wild type SEPT2 incorporates into the filament (top), G mutant does not incorporate into the filament (middle), and the NC mutant blocks SEPT2 Δ15 filaments by interacting with SEPT2 Δ15 (bottom).