aquaporin


Also found in: Dictionary, Thesaurus, Legal, Financial, Acronyms, Encyclopedia, Wikipedia.

channel

 [chan´el]
a passage, cut, or groove through which something can pass or flow across a solid structure.
calcium channel (calcium-sodium channel) a slow voltage-gated channel very permeable to calcium ions and slightly permeable to sodium ions, existing in three subtypes designated L, M, and N and located throughout the body; calcium channels are the main cause of action potentials in certain smooth muscles, and the N channels regulate neurotransmitter release.
fast channel a protein channel, such as a sodium channel, that becomes activated relatively quickly; a fast voltage-gated channel has a much lower activation potential than does the slow type. See also slow channel.
ligand-gated channel a protein channel that opens in response to the binding of a molecule (the ligand) to the protein, which causes a conformational change in the protein molecule. See also voltage-gated channel.
potassium channel a slow voltage-gated channel selective for the passage of potassium ions, found on the surface of a wide variety of cells, including nerve, muscle, and secretory cells; its functions include regulation of cell membrane excitability, regulation of repetitive low frequency firing in some neurons, and recovery of the nerve fiber membrane at the end of the action potential.
protein channel a watery pathway through the interstices of a protein molecule by which ions and small molecules can cross a membrane into or out of a cell by diffusion; protein channels play a vital role in depolarization and repolarization of nerve and muscle fibers, and may have physical characteristics such as shape or diameter that particularly attract certain ions.
slow channel a protein channel such as the calcium channel that is slow to become activated; a slow voltage-gated channel has a much higher activation potential than does the fast type. See also fast channel.
sodium channel a type of fast channel selective for the passage of sodium ions. Voltage-gated sodium channels are the main causes of depolarization and repolarization of nerve membranes during the action potential. In cardiac cells they produce phase 0 of the action potential.
voltage-gated channel a protein channel that can be opened or closed in response to changes in the electric potential across a cell membrane. See also ligand-gated channel.
water channel a channel in a cell membrane that permits passage of water molecules; chemical substances such as vasopressin cause the opening of new channels and increase permeability.

aquaporin

(ak-kwă-pōr'in),
A member of a family of transmembrane channel proteins found in epithelial membranes that serve to regulate transepithelial water movement in tissues involved in body fluid homeostasis.
[L aqua, water, + porus, channel, pore, + -in]

aquaporin

[ak′wah-po′rin]
any of a family of proteins found in plasma membranes and forming a functional component of water channels.

aquaporin

(ak″wă-por′ĭn) [ aqua + porin]
A cell membrane protein that lets water flow into and out of cells.
Mentioned in ?
References in periodicals archive ?
In order to test for aquaporin function and potential control of function in gametophyte stages, gametophytes were exposed to desiccating levels of osmolytes with and without mercury exposure.
Despite their postulation years earlier, the discovery of the first aquaporin actually occurred during a study of the Rh antigens of the red blood cell (RBC) membranes in Peter Agre's laboratory at Johns Hopkins.
Downregulation of renal aquaporins in response to unilateral ureteral obstruction.
Still, control of aquaporins alone cannot maintain water balance in a desiccating environment.
elegans, the fact that the two mammalian aquaporin glycerol-transporting channels are downregulated by insulin raises the possibility that glucose may have a life-span-shortening effect in humans, and, conversely, that a diet with a low glycemic index may extend human life span," the researchers said.
Yet, not until the 1990s were the first members of the aquaporin (AQP) family identified.
The structure of the yeast aquaporin that we have determined can be used to create inhibitors for human aquaporins, and this may in the long term lead to drugs that slow the growth of a cancer tumour," says Karin Lindkvist.
Aquaporin water channels facilitate tumor cell migration and metastasis.
Structural determinants of water permeation through aquaporin 1.
Increase the naturally hydrating aquaporin activity and functionality in every cell by using piptadenia colubrina peel extract (from a tree in the Brazilian rain forest) and found in Cell Youth Actif and Total Age Corrector.
A mechanism by which the osmotic laxative magnesium sulphate increases the intestinal aquaporin 3 expression in HT-29 cells.