And we examined this particular method when we discussed epinephrine signaling. So epinephrine can actually dissociate from its side and that can basically stop that process from taking place. We also discussed the fact that G protein so in the case of epinephrine signaling and also in the case of the EGF signaling, there are G proteins that contain GPA's activity. And what that means is they actually have a built in timer that allows it to deactivate the process after some time has passed. And we also discussed phosphatase. So many of these pathways, actually all the pathways depend on protein kinases.