aquaporin

(redirected from Aquaporins)
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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″wă-por′ĭn) [ aqua + porin]
A cell membrane protein that lets water flow into and out of cells.
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References in periodicals archive ?
This low responsiveness to water deficit can be explained by the unique location of these aquaporins in the endoplasmic reticulum [59], an organelle with tortuous structure and high surface-to-volume ratio with high demand for osmotic balance volume and, therefore, may not require the water transport mediated by aquaporins [59].
Aquaporin 3 (AQP3) is the most abundant aquaglyceroporin in human epidermis, being responsible for facilitating the transportation of water, glycerol and other solutes like urea through membranes.
In order to study the process he and his colleagues used living cells which expressed the "fluorescent" protein GFP, attached to the aquaporin AQP9.
Proteomic knowledge of human aquaporins. Proteomics 2006;6:5637-49http://dx.doi.org/10.1002/pmic.200600212.
Mr Agre discovered aquaporins - proteins which transport water between the dermis and the epidermis.
Aquaporins (AQPs) are an important family of proteins that efficiently channel water through the cell membranes.
Aquaporins. Now that we have reviewed the fundamentals of urinary concentration and dilution in the kidneys, let us take a closer look at the mechanisms underlying water movement through the tubule walls.
Aquaporins: water selective channels in biological membranes.
Aquaporins (AQPs) are a family of transmembrane proteins that can act as water and other small molecules channels.
The water channels aquaporins (AQPs) may have a relevant role in the establishment and maintenance of DN because of their role in the regulation of fluid balance in the kidney and since polyuria is a very early clinical sign of diabetes.
Therefore, aquaporins (AQPs) are likely to play a role in water transport that is essential for appropriate hepatobiliary tract function.