1. Pgp is a transmembrane protein which acts as a drug efflux pump to extrude toxic hydrophobic compounds from the cell.

2. The mechanism for Pgp actions involves phosphorylation and interaction between protein domains.

3. Pgp substrate recognition and interaction is critically linked to lipid biochemistry.

4. Pgp is also involved in other cellular activities ranging from signal transduction to modulation of apoptosis to regulation of osmotic pressure. Phosphorylation may be the means of interconverting Pgp among its different active forms.