Signal pathway knockout

Normal cells exposed to hormone H show 4-fold reporter activation. Receptor-knockout cells show 1.1-fold; kinase-knockout cells show 1.0-fold; adding active kinase restores 3.8-fold only in kinase-knockout cells.

1. The receptor acts upstream of the kinase.
2. Active kinase bypasses the missing kinase, not the missing receptor test shown here.
3. Reporter activation is the outcome.