By Aviv Paz (

Many drugs are toxic in high concentrations, therefore they are administered in specific doses that ensure drug activity without side-effects or even acute and lethal reactions. The organic anion transporting polypeptide 1B1 (OATP1B1) is a liver protein responsible for the clearance of many drugs from the bloodstream. Thus, the levels of activity of OATP1B1 control the concentration of these drugs in the body. Consequently, reduced drug clearance by OATP1B1 could lead to severe toxicities.

In a study published in the journal Clinical Cancer Research entitled: “Regulation of OATP1B1 function by tyrosine kinase-mediated phosphorylation” Dr. Paz collaborated with the Sprowl laboratory at the University at Buffalo, who spearheaded this study. They identified a novel drug-induced mechanism that lowers the activity levels of OATP1B1. This has broad implications for the clearance of many drugs by OATP1B1 and for preventing harmful interactions between drugs administered in conjunction (drug-drug interactions).