Integration

Most eukaryotic membrane proteins are integrated into the lipid bilayer during their synthesis at the endoplasmic reticulum (ER). Their integration occurs with the help of a protein-conducting channel formed by the heterotrimeric Sec61 membrane-protein complex.

The crystal structure of an archaeal homolog of the complex suggests mechanisms that enable the channel to open across the membrane and to release laterally hydrophobic transmembrane segments of nascent membrane proteins into lipid.

Types

 receptors

• signal transduction proteins

 channels

• ABC transporters
• organic solute transporters
• inorganic solute transporters
• ion channels
• primary pumps (ATPases)

References

 Rapoport TA, Goder V, Heinrich SU, Matlack KE. Membrane-protein integration and the role of the translocation channel. Trends Cell Biol. 2004 Oct;14(10):568-75. PMID: #15450979#