FIGURE 5.

SecA affects membrane targeting of DivIVA. (A) Distribution of DivIVA in membrane and cytoplasmic fractions of wild type cells (strain NIG1121), and in cells of the temperature sensitive secA341 mutant (strain NIG1152) during growth at 37°C. DivIVA concentrations were determined by Western blotting (upper panel), and a parallel Western blot using an antiserum directed against SecY was included as a control (lower panel, T – total extract, C – cytoplasm, M – membrane). Note that membrane samples have been concentrated 10-fold in the course of their isolation. (B) Densitometric quantification of Western blot signals from four independent experiments are shown in panel A. Values are given as ratios of DivIVA and SecY levels detected in the membrane fraction of secA341 cells relative to their levels in wild type cells at the indicated temperatures. Asterisks are used to indicate significance levels: P < 0.05 (*) or P < 0.005 (**).