Transmembrane domain

Transmembrane Domain

Structure of an AMPA receptor, highlighting the transmembrane domain.

A transmembrane domain is a region of a protein that spans the lipid bilayer of a cell membrane. These domains are typically composed of hydrophobic amino acids that interact with the hydrophobic core of the lipid bilayer, allowing the protein to be stably embedded within the membrane.

Structure

Transmembrane domains are often composed of one or more alpha helices or, less commonly, beta barrels. The alpha helical structure is the most common motif found in transmembrane proteins. These helices are typically 20-25 amino acids in length, which is sufficient to span the hydrophobic core of the lipid bilayer.

Function

Transmembrane domains play crucial roles in the function of integral membrane proteins. They can serve as channels or pores for the transport of ions and molecules across the membrane, as seen in ion channels and transporters. They can also be involved in signal transduction processes, where they transmit signals from the extracellular environment to the cell's interior.

Examples

One well-studied example of a protein with transmembrane domains is the AMPA receptor, a type of glutamate receptor that mediates fast synaptic transmission in the central nervous system. The AMPA receptor contains multiple transmembrane domains that contribute to its function as an ion channel.

Related pages

• Cell membrane
• Integral membrane protein
• Ion channel
• Signal transduction