 So, while much of I have said depends on early models, indirect experiments and everything, we have gone through a revolution the last 30 years. There are so many membrane proteins for which we now have not just structures, but high-resolution structures that are so great that I can see lipids. In parallel to that, we can do simulations on time and length scales where I can actually simulate membrane proteins and see how a lipid will bind to them. And then we can do this. This is an old study of ours, actually, but here we have part of a voltage-gated ion channel where the oreate solid parts are examples of lipids we found in a new x-ray structure, while these licorice parts here are lipids from the simulation. We started them far away and then they've used and found their binding site. So, it appears both the simulation and the x-ray structure predict that you would have lipids very tightly bound to certain part of the structure. If they were not tightly bound, we would not see them in the x-ray crystal because they have to be the same confirmation in every copy of the crystal. We can test that even more in simulations because in simulations I can check how fast the lipids are moving and diffusing around the membrane protein. Remember, Singer Nicholson, proteins should diffuse in a sea of lipids. That's not quite true, if you ask the simulations. The protein here is white. I don't care about the proteins, just the lipids. The lipids far out here in red, they are the ones that are diffusing freely as if they were in a lake. But as I'm getting closer to the protein here, we turn into yellow, green, blue and eventually black territory. And that means that the lipids are hardly moving at all. In fact, we have at least one, some of these in this cavities here, the lipids are so tightly bound that they never move. They're literally part of the structure. And even around that, we typically have one, if not two layers of lipids that there's some sort of coat around the protein. It's technically true that the protein is diffusing in lipids, but it is diffusing together with one or two layers of lipids around it. The lipids are effectively part of the protein. Look at the size here. The dark part here is almost twice the size of the protein itself. We can look at that another way by checking the average jump length of lipids when they diffuse and see how that varies. As we get further away from the protein, things move faster and faster and faster. It's pretty much just in the outskirts of this box, right, that we reach the region where they behave like bulk lipids, lipids that are in a pure lipid bilayer. Anywhere close to the protein, we're going to have a significant influence probably here. And we can look at this as probability of moving a certain length. And here too, we see that we need to get almost a factor two away from the protein before we behave like bulk lipids. Simulations are cool. This might not be numerically exactly correct, but the properties definitely make sense. And it shows that we have a much larger surrounding around proteins than we would expect just from looking at the structures.