Biogenesis of inner membrane proteins in Escherichia coli

For a long time, it was generally assumed that the biogenesis of inner memb rane proteins in Escherichia coli occurs spontaneously, and that only the t ranslocation of large periplasmic domains requires the aid of a protein mac hinery, the Sec translocon. However, evidence obtained in recent years indi cates that most, if not all, inner membrane proteins require the assistance of protein factors to reach their native conformation in the membrane. Her e, we review and discuss recent advances in our understanding of the biogen esis of inner membrane proteins in E. coli.