Transporter

Transporter refers to a type of protein that facilitates the movement of substances across a cell membrane. Transporters are integral membrane proteins; that is, they exist within and span the membrane across which they transport substances. The proteins may assist in the movement of substances by facilitated diffusion or active transport.

Types of Transporters

There are several types of transporters, including:

• Ion transporter: These transporters move ions across a membrane, often against their concentration gradient, using ATP as an energy source. Examples include the sodium-potassium pump, the hydrogen potassium ATPase, and the sodium-calcium exchanger.

• Glucose transporter: These transporters facilitate the transport of glucose, a type of sugar, across the plasma membranes of cells.

• Amino acid transporter: These transporters facilitate the transport of amino acids, the building blocks of proteins, across the plasma membranes of cells.

• Nucleoside transporter: These transporters facilitate the transport of nucleosides, the building blocks of nucleic acids, across the plasma membranes of cells.

Function

Transporters play a crucial role in the movement of substances across cell membranes. They are responsible for the uptake of nutrients, the removal of waste products, and the overall maintenance of intracellular homeostasis.

Clinical significance

Transporters are targets for a variety of drugs, including antidepressants, antipsychotics, and antibiotics. They can also be involved in drug resistance, as in the case of the multidrug resistance protein.

See also

• Membrane transport protein
• Active transport
• Facilitated diffusion