Method number one is the fact that because we have a G protein involved and G proteins have Gtpa's activity, what that means is they have a built in clock that allows it to actually shut itself down following activation. So sometime after this has been activated into the GTP form, this green structure, the G protein, because it has Gtph activity, it is able to actually take a water molecule from the cytoplasm and hydrolyze the GTP back into GDP. And once it inactivates itself, this can no longer stimulate the rest of the process. And so this pathway essentially shuts down as a result. So cells can terminate the pathway by using Gtpa's activity of G proteins and that is built in into that molecule. Number two, these cells can also actually terminate the pathway by using a class of molecules we call phosphatases.