Summary of the cell surface PSMα1–4 and the colony spreading in S. aureus gene knockout strains.
PSMα1–4 and δ-toxin are presented as orange and blue dots, respectively. Knockout of δ-toxin increases the amount of cell surface PSMα1–4. In contrast, knockout of PSMα1–4 does not affect the amount of cell surface δ-toxin. The amount of cell surface PSMα1–4 and the colony-spreading activity in the wild-type strain, the δ-toxin knockout strain, the PSMα1–4 knockout strain, and the PSMα1-4/δ-toxin knockout strain is summarized in the lower part of this figure. The amount of cell surface PSMα1–4 is a determinant of colony-spreading activity.