So these became known as MDR proteins or simply P glycoproteins. So actually they're not only proteins, they're glycoproteins because they have sugar components. So we see that multidrug resistance was shown to be a result of the expression of these membrane proteins that became known as multi drug resistant proteins. MDR proteins, they use energy to pump drugs out of the cell before the drugs can actually carry out or elicit their effects. And this is what our MDR protein looks like. So notice, the MDR protein consists of four domains.