Well, basically a lipid raft is a section of the membrane that contains a high concentration of cholesterol molecules as well as the glycophospholipids. And because we have a high concentration of these lipids within the area of the membrane, what that does is ultimately it increases the rigidity and makes that membrane less fluid. Because if in a given section, if we're in that lipid rack region, we have many more of these large molecules. So cholesterol molecules are relatively large, and these glycophosolipids are also very large, and they're packed densely to this region. That area will have a lower amount of movement. And so if we have lower movement, that means we have more of these interactions.