FIGURE 9.

The N-terminal fragment of SOK1 can induce cell death with high efficiency, and this is dependent on its kinase activity and amino acids 275-292. M2-flagged versions of SOK1^ΔC, SOK1^ΔCK49R, SOK1^ΔCT174A, and SOK1^ΔC4A were transfected into HEK293 cells. A, the levels of expression of the different mutants were determined by Western blotting using anti-M2 antibody. B, the kinase activity of each mutant toward the unspecific substrate myelin basic protein (MBP) was determined after immunoprecipitation with the M2 antibody. C, the ability of each mutant to induce cell death was assessed by determining the percentage of non-viable cells by trypan blue exclusion. Shown is the mean and S.D. of four independent experiments. ^*, p < 0.05 versus SOK1^ΔC. WT, wild-type.