1. The problem statement, all variables and given/known data Describe the methods by which proteins are clustered in the plasma membrane. 2. Relevant equations There are none really; it's theory. 3. The attempt at a solution I understand that the proteins bond with the cytoskeleton (actin microfillaments and intermediate fillaments), but I can't seem to think of the second method. I do know that it is not that the proteins in the plasma membrane bond with the extracellular matrix. Perhaps it has something to do with the proteins bonding together? Such as polypeptides forming disulfide bridges, hydrogen bonds, or the like? Any insight would be greatly appreciated.