Xenbase is undergoing scheduled maintenance Wednesday, June 14 and Thursday, June 15, 2023. Xenbase will be unavailable on those days.

Click on this message to dismiss it.
Click here to close Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly. We suggest using a current version of Chrome, FireFox, or Safari.
Mol Pharmacol 2000 Mar 01;573:576-88.
Show Gene links Show Anatomy links

Cloned human aquaporin-1 is a cyclic GMP-gated ion channel.

Anthony TL , Brooks HL , Boassa D , Leonov S , Yanochko GM , Regan JW , Yool AJ .

Aquaporin-1 (AQP1) is a member of the membrane intrinsic protein (MIP) gene family and is known to provide pathways for water flux across cell membranes. We show here that cloned human AQP1 not only mediates water flux but also serves as a cGMP-gated ion channel. Two-electrode voltage-clamp analyses showed consistent activation of an ionic conductance in wild-type AQP1-expressing oocytes after the direct injection of cGMP (50 nl of 100 mM). Current activation was not observed in control (water-injected) oocytes or in AQP5-expressing oocytes with osmotic water permeabilities equivalent to those seen with AQP1. Patch-clamp recordings revealed large conductance channels (150 pS in K(+) saline) in excised patches from AQP1-expressing oocytes after the application of cGMP to the internal side. Amino acid sequence alignments between AQP1 and sensory cyclic-nucleotide-gated channels showed similarities between the cyclic-nucleotide-gated binding domain and the AQP1 carboxyl terminus that were not present in AQP5. Competitive radioligand-binding assays with [(3)H]cGMP demonstrated specific binding (K(D) = 0.2 microM) in AQP1-expressing Sf9 cells but not in controls. These results indicate that AQP1 channels have the capacity to participate in ionic signaling after the activation of cGMP second-messenger pathways.

PubMed ID: 10692499
Article link: Mol Pharmacol
Grant support: [+]

Species referenced: Xenopus laevis
Genes referenced: aqp1 aqp5 mip tnpo1