July 3, 1998 Several weeks ago cardiologists representing 72
organizations from all over the world announced that a new drug
called tirofiban -- also known as aggrastat -- could reduce the
risk of death in unstable angina patients by 47%. The drug
attaches to and blocks biochemical doorways on platelet cells
called IIb/IIIa receptors. When bound to these receptors, the
drug keeps fibrinogen -- a protein found in the blood -- from
adhering to platelets, thereby preventing the formation of
platelet thrombi, which can cause arterial blockage. The lab of
Joel Bennett, MD, a professor of medicine, has been working on
the molecular biology of the IIb/IIIa receptor for the last 20
years. His lab's discovery of the receptor, its amino acid
sequence, and how it works in conjunction with proteins like
fibrinogen laid the groundwork for these recent clinical
advances. In the last year, Bennett and colleagues have been
trying to find out how IIb/IIIa gets activated in the first
place. Platelets -- via the IIb/IIIa recept