Sandbox WWC4

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Aquaporin (AQP) The Water Channel of the cell

Aquqporin (AQP) is a integral membrane proteins that control the amount of water that travels in and out of the cell^[1]. Before the discovery of aquaporin by Peter Agre (1992); it was thought that water molecules leaked through the phospholipid bilayer one by one. However this could not be the case for cells that need to released and uptake water quickly like in the kidneys.

Aquaporins allow water to flow rapidly to the inside of cell then it would by crossing the bilayer.^[1] The presence of water channels increases membrane permeability to water^[1]. This protein is highly selective to water molecules and prevents the passage of ions and other solutes.There are multiple types of aquaporins in the human boby, some can allow the transport of other molecules such as glycerol,CO2, ammonia and urea. For example aquaporin 3 has a pore width of 8-10 Ångströms and allows the passage of hydrophilic molecules ranging between 150-200 Da^[1].

Water Orientation in AQP

Structure

AQP1 monomer contains 269 amino acid residues, which form two tandem repeats of three membrane-spanning α-helices.Aquaporin is a protien with six transmembrane alpha helices with the amino and craboxyl terminal tails located in the cytoplasm.^[2]. Water molecules traverse through the pore of the channel in single file^[1].Each monomer is able to channel water.There is a conserved Asn-Pro-Ala sequence that overlap in the middle of the lipid bilayer membrane which creates trail for the water molecules to be carried along in the channel.

The hydrogen-bonding interactions of water molecules with the polar side chains of Asn-76 and Asn-192 on the strictly conserved Asn-Pro-Ala sequence motifs were found to be essential for maintaining the connectivity of water flow in the narrow constriction region^[3].

Water Orientation in AQP

The hourglass shape allows the water flows, these water pores are completely impermeable to charged species, such as protons. Which is very important to the conservation of membrane's electrochemical potential^[1].

Water Enters

Water molecules enter aquaporin and move through the narrow channel by orienting themselves by the electrical field created channel wall.

-The water molecule is oriented with their oxygen atom facing down the channel.

-If water is flowing outside of the cell then the water molecule is oriented with the oxygen atom facing down.^[4]

Water Orientation in AQP

Aquaporin's channel contains asparagines that interact with the hydrogen bonds on the water molecule which allows the orientation of water.

The narrow pore acts to weaken the hydrogen bonds between the water molecules allowing the water to interact with the positively charged arginine, which also acts as a proton filter for the pore.^[2]

Function

There are thirteen known types of aquaporins in mammals, and six of these are located in the kidney. The most studied aquaporins are AQP1, AQP2, AQP3, and AQP4. The location of Aquaporin is usually found in the kidney, eye in the body. ^[4]

In the Kidney, they are found in the basolateral and apical plasma membranes of the proximal tubules and the limb of the loop of Henle in the kidney.Aquaporin are concentrated in the kidney is where there is a need to transporting large amounts of water in and out of the cell.^[4]

Water Orientation in AQP

Additionally, it is found in red blood cells, vascular endothelium, the gastrointestinal tract, sweat glands, and lungs.

References

↑ ^1.0 ^1.1 ^1.2 ^1.3 ^1.4 ^1.5 Takata K, Matsuzaki T, Tajika Y. Aquaporins: water channel proteins of the cell membrane. Prog Histochem Cytochem. 2004;39(1):1-83. PMID:15242101
↑ ^2.0 ^2.1 Murata K, Mitsuoka K, Hirai T, Walz T, Agre P, Heymann JB, Engel A, Fujiyoshi Y. Structural determinants of water permeation through aquaporin-1. Nature. 2000 Oct 5;407(6804):599-605. PMID:11034202 doi:10.1038/35036519
↑ PMID:PMC64684
↑ ^4.0 ^4.1 ^4.2 Rutkovskiy A, Valen G, Vaage J. Cardiac aquaporins. Basic Res Cardiol. 2013 Nov;108(6):393. doi: 10.1007/s00395-013-0393-6. Epub 2013, Oct 25. PMID:24158693 doi:http://dx.doi.org/10.1007/s00395-013-0393-6

Retrieved from "http://52.214.119.220/wiki/index.php/Sandbox_WWC4"

@@ Line 1: / Line 1: @@
 ==Aquaporin (AQP) The Water Channel of the cell==
-<StructureSection load='1h6i' size='350' side='right' caption='Aquaporin' scene='Aquaporin with ligand'>
+<StructureSection load='1h6i' size='350' side='right' caption='Aquaporin' scene='Aquaporin'>
+<scene name='69/696849/Hydrophobic_and_polar/1'>1H6I hydrophobic and polar</scene>
-This is a integral membrane proteins that control the amount of water that travels in and out of the cell<ref name="Takata">PMID:15242101</ref>. Before the discovery of aquaporin, it was thought that water molecule just leaked through the phospholipid bilayer.
+Aquqporin (AQP) is a integral membrane proteins that control the amount of water that travels in and out of the cell<ref name="Takata">PMID:15242101</ref>. Before the discovery of aquaporin by Peter Agre (1992); it was thought that water molecules leaked through the phospholipid bilayer one by one. However this could not be the case for cells that need to released and uptake water quickly like in the kidneys.
-Aquaporins allow water to flow rapidly to the inside of cell then it would by crossing the bilayer.<ref name="Takata" />
+Aquaporins allow water to flow rapidly to the inside of cell then it would by crossing the bilayer.<ref name="Takata" /> The presence of water channels increases membrane permeability to water<ref name="Takata" />. This protein is highly selective to water molecules and prevents the passage of ions and other solutes.There are multiple types of aquaporins in the human boby, some can allow the transport of other molecules such as glycerol,CO2, ammonia and urea. For example aquaporin 3 has a pore width of 8-10 Ångströms and allows the passage of hydrophilic molecules ranging between 150-200 Da<ref name="Takata" />.
-This protein is highly selective to water molecules , preventing the passage of ions and other solutes.There are multiple types of aquaporins that can allow the transport of other molecules such as glycerol,CO2, ammonia and urea  by aquaglyceroporin. It depends on the size of the pore; aquaporin 3 channel has a pore width of 8-10 Ångströms and allows the passage of hydrophilic molecules ranging between 150-200 Da<ref name="Takata" />. Aquaporins water channel are impermeable to protons and other charged species
-Water molecules traverse through the pore of the channel in single file<ref name="Takata" />. The presence of water channels increases membrane permeability to water<ref name="Takata" />.
+[[Image:AQP-Figure-3-Full.gif|300px|left|thumb|Water Orientation in AQP]]
 '''Structure'''
-Aquaporin is  protien with six transmembrane alpha helices with the amino and craboxyl terminal located in the cytoplasm.<ref name="Murata">PMID:11034202</ref>
+AQP1 monomer contains 269 amino acid residues, which form two tandem repeats of three membrane-spanning α-helices.Aquaporin is a protien with six transmembrane alpha helices with the amino and craboxyl terminal tails located in the cytoplasm.<ref name="Murata">PMID:11034202</ref>. Water molecules traverse through the pore of the channel in single file<ref name="Takata" />.Each monomer is able to channel water.There is a conserved Asn-Pro-Ala sequence that overlap in the middle of the lipid bilayer membrane which creates trail for the water molecules to be carried along in the channel.
--Each monomer is able to channel water.
+The hydrogen-bonding interactions of water molecules with the polar side chains of Asn-76 and Asn-192 on the strictly conserved Asn-Pro-Ala sequence motifs were found to be essential for maintaining the connectivity of water flow in the narrow constriction region<ref name="Kong">PMID:PMC64684</ref>.
--There is a conserved Asn-Pro-Ala sequence that overlap in the middle of the lipid bilayer membrane which creates the'hourglass' structure of the aquaporin.
--The hourglass shape allows the water flows, these water pores are completely impermeable to charged species, such as protons.
+[[Image:AQP-Figure-4-Full.gif|300px|right|thumb|Water Orientation in AQP]]
-Which is very important to the conservation of membrane's electrochemical potential<ref name="Takata" />.
+The hourglass shape allows the water flows, these water pores are completely impermeable to charged species, such as protons. Which is very important to the conservation of membrane's electrochemical potential<ref name="Takata" />.
 <scene name='69/696849/Chains_of_aquaporin/1'>Chains of Aquaporin (Click to View)</scene>
@@ Line 23: / Line 26: @@
 -The water molecule is oriented with their oxygen atom facing down the channel.
--If water is flowing outside of the cell then the water molecule is oriented with the oxygen atom facing  down.
+-If water is flowing outside of the cell then the water molecule is oriented with the oxygen atom facing  down.<ref name="Cardiac" />
 [[Image:Kljgfklgj.jpg|300px|left|thumb|Water Orientation in AQP]]
@@ Line 37: / Line 40: @@
 '''Function'''
-There are thirteen known types of aquaporins in mammals, and six of these are located in the kidney. The most studied aquaporins are AQP1, AQP2, AQP3, and AQP4.The location of Aquaporin is usually found in the kidney, eye in the body.
+There are thirteen known types of aquaporins in mammals, and six of these are located in the kidney. The most studied aquaporins are AQP1, AQP2, AQP3, and AQP4. The location of Aquaporin is usually found in the kidney, eye in the body. <ref name="Cardiac"> PMID: 24158693 </ref>
-In the Kidney, they are found in the basolateral and apical plasma membranes of the proximal tubules and the limb of the loop of Henle in the kidney.Aquaporin are concentrated in the kidney is where there is a need to transporting large amounts of water in and out of the cell.
+In the Kidney, they are found in the basolateral and apical plasma membranes of the proximal tubules and the limb of the loop of Henle in the kidney.Aquaporin are concentrated in the kidney is where there is a need to transporting large amounts of water in and out of the cell.<ref name="Cardiac" />
-[[Image:F2.large.jpg|300px|left|thumb|Water Orientation in AQP]]
+[[Image:F2.large.jpg|300px|right|thumb|Water Orientation in AQP]]
-Aquqporin was also found in the plants.
-If a person is identified with severe or total deficiency in aquaporin-1. They are generally healthy, they might have a disorder that cause an increase in urine production.
 Additionally, it is found in red blood cells, vascular endothelium, the gastrointestinal tract, sweat glands, and lungs.
+== References ==
+<references/>
 ----

Sandbox WWC4

From Proteopedia

Current revision

Aquaporin (AQP) The Water Channel of the cell

Water Enters

References

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