Crystal structure of Potassium channel Kv1.2/2.1 Chimera. Calculated hydrocarbon boundaries of the lipid bilayer
are indicated by red and blue dots.
A membrane protein is a protein molecule that is attached to, or associated with the membrane of a cell or an organelle.
20–30% of all genes in genomes code for membrane proteins. They are targets of over 50% of all modern medicinal drugs.
Membrane proteins perform a variety of functions vital to the survival of organisms:
- Membrane receptor proteins relay signals between the cell's internal and external environments.
- Membrane transport proteins move molecules and ions across the membrane.
- Membrane enzymes have many activities.
- Cell adhesion molecules allow cells to identify each other and interact. For example proteins involved in immune response.
Images for kids
Schematic representation of transmembrane proteins: 1. a single transmembrane α-helix (bitopic membrane protein) 2. a polytopic transmembrane α-helical protein 3. a polytopic transmembrane β-sheet protein The membrane is represented in light-brown.