A membrane transport protein (or simply transporter) is a membrane protein involved in the movement of ions, small molecules, or macromolecules, such as another protein, across a biological membrane. Transport proteins are integral transmembrane proteins; that is they exist permanently 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. These mechanisms of action are known as carrier-mediated transport.
Types
(Grouped by Transporter Classification database categories)
1: Channels/pores
- Facilitated diffusion
Facilitated diffusion occurs in and out of the cell membrane.
2: Electrochemical potential-driven transporters
- Mitochondrial membrane transport protein
- Glucose transporter
- Neurotransmitter transporters
- Glutamate/aspartate transporters
- GABA transporters
- Glycine transporters
- Monoamine transporters, including:
- Dopamine transporter (DAT)
- Norepinephrine transporter (NET)
- Serotonin transporter (SERT)
- Vesicular monoamine transporters (VMAT)
- Adenosine transporters
- Vesicular acetylcholine transporter (VAChT)
3: Primary active transporters
- ATP-binding cassette transporter genes
- P-glycoprotein
- CD98
- V-ATPase
- Ion transporters
- Na+/K+-ATPase
- Plasma membrane Ca2+ ATPase
- Proton pump
- Hydrogen potassium ATPase
- Sodium-chloride symporter
4: Secondary active transporters
Symporters transport two or more ions together in the same direction, like the Bacterial Leucine Transporter, or antiporters in the opposite direction.
5: Incompletely characterized transport systems
- 9.A.50: Karyopherin
Ungrouped
- CD36
See also
- Carrier protein
- Cotransport
- Cotransporter
- Ion channel
- P-loop
- Solute carrier family (classification)
- TC number (classification)
- Vesicular transport protein
References
External links
- "Transport protein" at Dorland's Medical Dictionary
- DDI Regulatory Guidance Request a guide to drug-drug interaction regulatory recommendations.