And this causes a cross phosphorylation process in which both of these beta units are actually phosphorylated in the presence of ATP. And what that does is it activates this insulin receptor. And because of the fact that this receptor itself contains a tyrosine protein kinase we also called the insulin receptor, the insulin receptor protein kinase. So once again, when the insulin primary messenger, a peptide hormone, moves into its cavity that is created by the two alpha subunits the closure of the two alpha chains causes the two beta chains to move closer together and this leads to crossfosphorylation as shown here and here. That basically changes the confirmation of those beta subunits and that activates those beta subunits. So we see the binding of the insulin on one side of that receptor activates it on the other side and so that signal can basically be transduced passed down from the outside to the inside of that cell.