M O D U L A T O R
alomone labs
M olecula r Tools for the Neuroscie nc e Co mm unity
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Membrane Water Transport Proteins - Aquaporins
Yo na Bismuth, M.Sc.
The mechanism of water movement across cell membranes remained
unclear until 1992, when the first water specific channel was identified
in the human erythrocyte membrane. 1 It belongs to an ancient protein
family (MIP) found in most li ving or ganisms, fr om pr okaryotes to
mammalians and plants.2 This protein, as well as the others recently
di scovered wer e named "aquapori ns " (AQP's). Today, ten w ater
c h a n n el s h a v e be e n i d e n t i f i e d . T he y s ha r e t he s a m e 6
transmembrane domains structure but differ in their tissue distribution
as well as in their regulatory mechanism.
AQP1 is found almost in all tissues. In kidney, it i s located in the
proximal tubule and in the descending thin limb. It is believed to be
responsible for constitutive water reabsorption.3 AQP1 deficient mice
do not express any lethal pathology but are unable to produce
Anti-Aquaporin 1
( AQP1, CHIP28)
concentrated urine. 4 Surprisingly, it has also been found that they
had troubles in lipid metabolism when fed a lipid rich diet. 5 Both
AQP2 and AQP3 are found in the plasma membrane of the renal
collecting duct epithelial cells. They are respectively located in the
apical and basolateral side of the cells.
The abundance and the specific location of the different aquaporins
in the kidney make them excellent markers of specific r egions in
this tissue. AQP4 is the predominant channel water in brain and its
distribution suggests it is involved in the regulation of extravascular
water. 6 Most of the mechanisms of aquaporins functions are still
unknown. However, the importance of water movement in living
organism and the large distribution of these pr oteins suggest the
importance of research in this field.
Immunohistochemical staining of Aquaporin 1 with
Anti-Aquaporin 1 (#AQP-001) in rat kidney.
The counterstain was methylene blue.
Cat. # AQP-001
50 µl $98.00
0.2 ml $320.00
Epitope: Peptide KVWTS GQVEE YDLDA DDIN, corresponding to residues 243-261
of human AQP1.
Epitope location: Intracellular, C-terminus.
Homology with other species: Rat, mouse, cattle, sheep - identical; dog - 18/19
residues identical; frog (Rana esculenta), toad (Bufo marinus) - 14/19 residues identical.
Reactivity confirmed: Rat, human.
Western blotting: Rat kidney membranes (1:1000).
Immunohistochemistry: Rat kidney sections.
Control antigen included in price.
References using thi s antibody:
1. Quigley, R. et al. (1998) J. Membr. Biol. 164, 177.
2. Mit tal, A. et al. (2000) Life Sci., 66, 1471.
Membrane Water Transport Proteins - Aqua porins
1
2
45
36
29
24
20
14
Western blotting of rat kidney membranes:
1. Anti-Aquaporin 1 (#AQP-001) (1:1000).
2. Anti-Aquaporin 1, preincubated with the
control peptide antigen.
MODULAT OR Is sue No. 15 Summer 2001
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M O D U L A T O R
alomone labs
M olecula r Tools for the Neuroscie nc e Co mm unity
Anti-Aquaporin 2
(AQP2, AQP-CD, WCH-CD)
Immunohistochemical staining of Aquaporin 2 with
Anti-Aquaporin 2 (#AQP-002) in rat kidney.
The counterstain was methylene blue.
Cat. # AQP-002
50 µl $98.00
0.2 ml $320.00
Epitope: Peptide (KY)RQS VELHS PQSLP RGSKA, corresponding to residues 254-271 of rat AQP2.
Epitope location: Intracellular, C-terminus.
Homology with other species: Mouse - identical; human, sheep - 17/18 residues identical.
Reactivity confirmed: Rat, human
Western blotting: Rat kidney membranes (1:200).
Immunohistochemistry: Rat kidney sections.
Control antigen included in price.
1
2
66
55
45
36
29
24
References using thi s antibody:
1. Mit tal, A. et al. (2000) Life Sci., 66, 1471.
Anti-Aquaporin 3
(AQP3, GLIP)
Cat. # AQP-003
50 µl $98.00
0.2 ml $320.00
Western blotting of rat kidney membranes:
1. Anti-Aquaporin 2 (#AQP-002) (1:200).
2. Anti-Aquaporin 2, preincubated with the
control peptide antigen.
Immunohistochemical staining of Aquaporin 3 using
Anti-Aquaporin 3 (#AQP-003), in mouse kidney.
T he immunor eactive pr oduct (bla ck)
f orms rings marking th e cross-sec tion
o f ducts. The counterst ain is the
f luoresce nt dye DAPIC (blue).
Epitope: Peptide (C)STEA ENVKL AHMKH KEQI, corresponding to residues 275-292
of rat AQP3.
Epitope location: Intracellular, C-terminus.
Homology with other species: Mouse - 17/18 residues identical; sheep,
human - 15/18 residues identical.
Reactivity confirmed: Rat, mouse.
Western blotting: Rat kidney membranes (1:200).
Immunohistochemistry: Rat kidney sections.
Control antigen included in price.
Membrane Water Transport Proteins - Aqua porins
1
2
97
66
45
31
20
14
Western blotting of rat kidney membranes:
1. Anti-Aquaporin 3 (#AQP-003) (1:200).
2. Anti-Aquaporin 3, preincubated with the
control peptide antigen.
MODULAT OR Is sue No. 15 Summer 2001
2
M O D U L A T O R
alomone labs
M olecula r Tools for the Neuroscie nc e Co mm unity
Anti-Aquaporin 4
(AQP4, WCH4, Mercurial-Insensitive Water Channel)
Cat. # AQP-004
50 µl $98.00
0.2 ml $320.00
Immunohistochemical staining of Anti-Aquaporin 4
receptors with Anti-Aquaporin 4 (#AQP-004), in
rat cerebral cortex.
Axons oriented perpendicular surface and axons
oriented parallel to cortical surface were stained
black. The counterstain was methylene blue.
Epitope: GST fusion protein with residues 249-323 of rat AQP4.
Epitope location: Intracellular, C-terminus.
Homology with other species: Mouse, bovine, human, and rabbit - respectively, 73/75,
71/75, 69/75, and 64/75 residues identical.
Reactivity confirmed: Rat.
Western blotting: Rat brain membranes (1:1000).
Immunohistochemistry: Rat brain sections.
Control antigen included in price.
1
2
117
97
66
45
Western blotting of rat brain membranes:
1. Anti-Aquaporin 4 (#AQP-004) (1:1000).
2. Anti-Aquaporin 4, preincubated with the
control antigen.
R e f e r e n c e s
1. Denker, B .M. et al. (1988) J. Biol. Chem. 263, 15634.
2. Chepelinsky, A . B. (1994) In “Handbook of Membrane
Channels,” pp.413-432. Academic Press, S an Diego.
3. Nielsen, S . et al. (1995) Am. J. Physiol. 268, F1023.
4. Ma, T. et al. (1998) J. Biol. Chem. 273, 4296.
5. Ma, T. et al. (2001) A m. J. Physiol. Cell Physiol. 280 (1):C126.
6. Nielsen, S. et al. (1997) J. Neurosci. 17, 171.
Protocols and detailed data sheets can be downloaded from our web site: www.alomone.com
Membrane Water Transport Proteins - Aqua porins
MODULATOR
Issue N o. 15 Summer 2001
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