So this he tail basically moves into the active side of this one and this heat tail moves into the active side of this one. And once they move in, what that active side does is it phosphorylates the tyrosine residues and it phosphorylates up to five residues found on this Sea terminal tail. In this case I've only shown four. So again, when we form the dimer, when this conformational change takes place, the carboxyilic, the Sea terminal end of one tyrosine kinase domain moves into the aesthetic side of the posing tyrosine kinase domain. And this is what we call the cross phosphorylation process. So in the same way that in the insulin pathway we carry out crossfosphorylation here, we also carry out crossfosphorylation, except in this particular case it's not the activation side, but it's the C terminal tail that moves into the active side of that opposing tyrosine kinase domain.