It's exposed only when we have this damaging taking place, when the endothelial cell is ruptured. Now, remember, we have all these other proteins floating around in close proximity. And as soon as the tissue factor is exposed on the membrane, what happens is another active form of another enzyme known as factor Seven, goes on and binds onto the tissue factor to form a dimer protein complex that now consists of two subunits known as tissue factor complex seven. So TF seven is basically this dimer protein complex that we form as soon as the rupturing process takes place. Now, once we form the TF seven complex, this dimer protein, this becomes acerine protease. And what that means is it goes on to activate other enzymes by cleaving them at specific amino acids on their amino acid sequence.