Now, recall from our previous discussion on protein kinase A, or simply PKA. The structure of protein kinase A consists of two types of domains. So we have two regulatory domains and we have two catalytic domains. And in its inactive form, all these domains interact to form this tetrimer structure. But when cap molecules go on and bind to the protein kinase aid, they bind to the regulatory sites of the regulatory structures and that causes the dissociation of the catalytic sites. And what that does is it opens up the active sites of the catalytic regions.