Anti-Aquaporin 2-ATTO-550


Product#:AQP-002-AO

Sizes:
50 µl


Aquaporin 2 (AQP-2) belongs to a family of membrane proteins that allow passage of water and certain other solutes through biological membranes. The family is composed of 13 members (AQP-0 to AQP-12). Little is known about the function of the two newest members, AQP-11 and AQP-12.

The aquaporins can be divided into two functional groups based on their permability characteristics: the aquaporins that are only permeated by water and the aquaglyceroporins that are permeated by water and other small solutes such as glycerol. This last group includes AQP-3, AQP-7, AQP-9 and AQP-10.1

The proteins present a conserved structure of six transmembrane domains with intracellular N- and C-termini. The functional channel is a tetramer but each subunit has a separate pore and therefore the functional channel unit, contains four pores.1

AQP-2 expression is largely confined to the kidney, particularly in the renal collecting duct where it performs a key role in water absorption and urine concentration. In fact, mutations in the AQP-2 gene produce hereditary nephrogenic diabetes insipidus, a disorder that results in the excretion of large volumes of urine.2

Under normal conditions, water homeostasis in the kidney is regulated through the anti-diuretic hormone vasopressin. Vasopressin is secreted from the pituitary gland and transported to the kidney through the blood where it binds to its receptor that is mainly expressed in cells of the collecting duct. The activated vasopressing receptor induces an increase in intracellular cAMP and subsequent PKA activation, which phosphorylates AQP-2. This phosphorylation causes the translocation of AQP-2 channels from intracellular vesicles to the cell membrane where it markedly increases water permeability.1, 3, 4

 

Alomone Labs has developed an antibody that is highly specific for AQP-2. The antibody was raised against a highly conserved epitope located at the C-terminus intracellular region of the rat AQP-2 channel. The Anti-Aquaporin 2 antibody (#AQP-002) has been tested in both Western blot analysis and immunohistochemical applications and can be used in rat, mouse and human samples.

 

We are pleased to offer a new version of this antibody that is directly labeled with an ATTO-550 fluorescent dye. ATTO dyes are characterized by strong absorption (high extinction coefficient), high fluorescence quantum yield, and high photo-stability. The ATTO-550 fluorescent label is related to the well known dye Rhodamine 6G and can be used with filters typically used to detect Rhodamine.

 

The antibody has been tested in immunohistochemical applications and is specially suited for experiments requiring simultaneous labeling of different markers.



Host:
Rabbit.
Epitope:
Peptide (C)RQSVELHSPQSLPRGSKA, corresponding to amino acid residues 254-271 of rat Aquaporin 2 (Accession P34080).
Putative epitope location:

Intracellular, C-terminus.

Homology:

Mouse  - identical; human, sheep - 17/18 residues identical.

 

Label:
ATTO-550. Maximun absorption 554 nm; maximum fluorescence 576 nm.  The fluorescence in excited most efficiently in the 540-565 nm range. This label is related to the well known dye Rhodamine 6G and can be used with filters typically used to detect Rhodamine. 

Applications:
Immunohistochemistry:
 
Paraffin embedded region of rat kidney showing a transversal cut of the inner medulla near to the renal papilla. Aquaporin 2 is detected in collecting ducts but not in thin segments of the loop of Henle. Slides were treated with citrate for antigen retrieval and then incubated overnight at 4°C with Anti-Aquaporin 2-ATTO-550  (#AQP-002-AO) (1:50)(Red). Nuclei are visualized with Hoechst 33342 (blue).

References:
1. King, L.S. et al. (2004) Nat. Rev. Mol. Cell Biol. 5, 687
2. Deen, P.M. et al. (1994) Science 264, 92.
3. Nielsen, S. et al. (2002) Physiol. Rev. 82, 205.
4. Robben, J.H. et al. (2006) Am. J. Physiol. Renal Physiol. 291, F257.
For research purposes only, not for human use.