Another big concept.
So, plasma membrane proteins can create unique domains.
Okay, we've talked about channels and things like that,
but in fact, you can have proteins that insert,
and then they like to interact with each other,
and we can create little postage stamps on the surface of the cell
that will allow you to have certain functionality.
So, for example, we talked about the lipid rafts.
In lipid rafts is a protein called caveolin, and that caveolin
is gonna be important for driving the cell sipping.
Well, caveolin likes to be in the lipid rafts,
so it likes to associate with other caveolae molecules.
And so, it's forming a specific domain.
So, that's what's being shown here.
Proteins associated with each other, forming a domain.
When they form a domain too, they can interact with the outside world.
So, you can have spot welds that hook a cell to the outside world
through transmembrane protein interactions because they're all linked there together.
A single protein might not be able to make that happen,
but if I have a hundred of them together in a membrane,
that's gonna be a pretty good spot weld to hold it in place.
Similarly, transmembrane proteins can also act --
interact with intracellular cytoskeletal proteins to provide signaling.
And we will talk about this.
About how we can have -- we can pull on a transmembrane protein,
and a mechanical stimulus will get to the nucleus.
Finally, by having proteins transmembrane on each side,
cells can interact one with another through those proteins.
And it may be the same protein, in which case it's called a homotypic interaction,
as shown here with the green squares.
It may be different proteins but having domains one
to another allow cells to communicate, to contact, to be held together.
And one protein doing that would not be enough.
We probably need to have a hundred or so on the surface of the cell.
Okay, so point here, plasma membrane proteins create unique domains.