Transmembrane proteins

Transmembrane proteins are a type of protein that span the entire biological membrane. They are integral to the function of all cells, playing key roles in various biological processes such as signal transduction, cell adhesion, and the establishment of cell polarity.

Structure

Transmembrane proteins have one or several parts that are hydrophobic, allowing them to interact with the fatty acid chains in the membrane's core. They also have hydrophilic parts exposed on the outside of the membrane, interacting with the aqueous environment. The hydrophobic regions usually consist of alpha helices, but can also include beta sheets.

Function

Transmembrane proteins perform a variety of functions necessary for the survival of organisms. They are involved in signal transduction, allowing cells to respond to external signals. They also play a role in cell adhesion, helping cells stick together and form tissues. Additionally, they are crucial for the establishment of cell polarity, which is essential for the proper functioning of many types of cells.

Types

There are two main types of transmembrane proteins: single-pass transmembrane proteins and multi-pass transmembrane proteins. Single-pass transmembrane proteins cross the membrane once, while multi-pass transmembrane proteins cross the membrane multiple times.

Examples

Examples of transmembrane proteins include G protein-coupled receptors, ion channels, and integrins. G protein-coupled receptors are involved in signal transduction, ion channels regulate the flow of ions across the membrane, and integrins are involved in cell adhesion and signal transduction.

See also

• Membrane protein
• Peripheral membrane protein
• Lipid bilayer