So inside that Er membrane, we have a set of proteins that are known as the SRP receptor, where SRP stands for the signal recognition particles. So what happens is this entire SRP and SRP ribosome complex binds to the SRP receptor. And when that takes place, another type of membrane, known as another type of protein in the er membrane, known as translocon, basically opens up. So adjacent to the SRP receptor is a protein channel known as the translocan. And the translocan is normally closed. But upon binding of the SRP ribosome complex to the SRP receptor on the er membrane, the channel opens up.