aquaporin


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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 ?
Metabolic impact of adipose and hepatic glycerol channels aquaporin 7 and aquaporin 9.
Lurin et al., "Function and regulation of seed aquaporins," Journal of Experimental Botany, vol.
In addition, lacrimal gland fluid secretion is mediated, in part, by the water channel, aquaporin 5 [49].
Aquaporin 4 (AQP4) mRNA levels 36 h after surgery revealed the inhibitory effects of Goreisan.
Higher plants had different regulating metabolism pathways in response to salt stress, such as eliminating the reactive oxygen species (ROS), synthetizing the osmotic regulators, utilizing ATPase to maintain the Na+ or Cl- ion concentrations, expressing late embriogenesis abundant protein (LEA) and transporting H2O molecules by aquaporin (AQP) etc.
Both BlastX and BlastP search results (eval 1e-44 over 42% identity and 4e-44 over 42%, respectively) indicated that the closest entry in the DDBJ/EMBL/GenBank was an aquaporin from the Demospongiae Suberites domuncula (accession no.
"This demonstrated that the aquaporin protein shows promise as an antigen in cattle vaccines to help prevent cattle fever tick infestations."
In this study, 468 genes in muscle and 316 genes in gill were upregulated, but the putative aquaporin gene was the top upregulated gene with a fold change of 113 times more in muscle at 3 than in the control (20).
(2002) Aquaporin water channels-from atomic structure to clinical medicine.
Further edema-associated protein studies were done with immunohistochemical techniques of aquaporin 4 (AQP4, rabbit, 1:200, Chemicon, Temecula, CA, USA), aquaporin 1 (AQP1, rabbit, 1 : 300, Chemicon) and glial fibrillary acidic protein (GFAP, rabbit, 1:1000, Dako, Glostrup, Denmark).
Oligoclonal bands (OBs) were not detected in the CSF and aquaporin 4 antibodies were negative.