The first type of protein transport that we have to discuss is called NA K, sodium, potassium, Atpace pump. And this is a pump, meaning it actually uses active transport. It utilizes an ATP molecule to establish an electrochemical gradient. So let's zoom in on this small cross section of our distal convolute tubule. We get the following diagram. So this is the inside the lumen of our distal convolute tubule.