Remember, this is the pathway used by the cells that ultimately stimulates the growth and division of epithelial and epidermal cells. So let's begin by focusing on how this pathway actually takes place, beginning with the binding of the EGF molecules onto their domains. So we have two EGF molecules bind onto each one of these domains shown in purple. And once the binding takes place, these two monomers associate with one another to form a dimer and that creates conformational changes in these two structures found in a cytoplasm. Now these two structures, and by the way, this is the EGF receptor these two structures actually contain tyrosine protein kinase domains. And once a conformational change takes place upon binding and the dimerization process, a cross phosphorylation takes place and the carboxyl terminal ends of this tail and this tail are phosphorylated by the active sides of these corresponding kinases.