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. And those catalytic regions are what we call the activated PKA. And now the activated PKA can go on to carry out its function. So what is its function?