Membrane protein assembly in vivo

This chapter reviews the current knowledge of membrane proteins and explains that they are handled by different targeting-translocation machineries from the perspective of possible structural constraints imposed by these machineries. This point of view has not been much elaborated up to now and there are not many clear examples of structural constraints that go beyond those imposed by the lipid bilayer itself. It also argues that such constraints do exist and that they cannot be ignored if one wishes to fully understand the principles underlying membrane protein structure. Membrane protein assembly processes are both diverse and highly evolved, attesting to the fact that strongly hydrophobic segments in proteins need to be guarded against and contained by tightly regulated processes in order not to wreak havoc on the cell.