Aquaporin Water Channels in the Kidney

Takata, Kuniaki; Matsuzaki, Toshiyuki; Tajika, Yuki; Ablimit, Abdushukur; Suzuki, Takeshi; Aoki, Takeo; Hagiwara, Haruo

doi:10.1267/ahc.38.199

Cited by 11 publications

(17 citation statements)

References 69 publications

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“…2; Takata et al, 2005). Among these isoforms, AQP1, AQP2, AQP3, and AQP4 are thought to be important for water reabsorption and are distributed in the proximal tubules, descending limbs of Henle's loop, connecting tubules, and collecting duct system, in accordance with the results from physiologically examined water permeability analyses (reviewed in fig.…”

Section: Aquaporins In the Kidneysupporting

confidence: 75%

Regulation of Aquaporins by Vasopressin in the Kidney

Ikeda

Matsuzaki

2015

Vitamins &Amp; Hormones

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Section: Aquaporins In the Kidneysupporting

confidence: 75%

Regulation of Aquaporins by Vasopressin in the Kidney

Ikeda

Matsuzaki

2015

Vitamins &Amp; Hormones

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“…The results presented here used a different technical approach than reported earlier [1] to address uncertainties regarding AQP8 localization that have been noted in the literature (see, for example [6,8]). The present findings provide additional strong support for the conclusion of Elkjaer et al [1]; i.e.…”

Section: Discussionmentioning

confidence: 99%

“…The aquaporins (AQPs) are a family of membranebound, homotetrameric water channel proteins that facilitate osmotically obliged water transport across membranes (reviewed in [3,6]). The monomers possess six transmembrane domains, five interconnecting loops, and N-and C-termini that reside in the cytosol.…”

Section: Introductionmentioning

confidence: 99%

Further evidence for AQP8 expression in the myoepithelium of rat submandibular and parotid glands

Wellner

Redman²,

Swaim

et al. 2005

Pflugers Arch - Eur J Physiol

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Previously (Wellner et al., Pflugers Arch 441:49-56, 2000) we suggested that the localization of the aquaporins (AQPs) AQP5 and AQP8 in the apical and basolateral membranes of rat submandibular gland (SMG) acinar cells, respectively, provides for transcellular water flow during saliva formation. While the localization of AQP5 in this gland has been verified in several laboratories, there have been differing reports regarding AQP8 localization. Other investigators subsequently reported that AQP8 is not expressed in the acinar or ductal cells of the major salivary glands of the rat, but in the myoepithelium of each gland. Thus, we have carried out additional studies: (1) to reassess the localization of AQP8 in the rat SMG and (2) to assess the localization of AQP8 in the rat parotid gland (PG). Initially, we compared the localizations of AQP8 with recognized basolateral markers in acinar cells [the Na+,K+-ATPase and the Na+-K+-2Cl- cotransporter (NKCC1)]. Our results indicated that Na+,K+-ATPase localized in both the basal and lateral membranes of rat SMG acinar cells, whereas AQP8 was detected only in the basal regions of the acini. In the rat PG, AQP8 was invested near intercalated ducts and adjacent acini, whereas NKCC1 localized in the basolateral membranes of acinar cells. As these results were suggestive of myoepithelial localization in both glands, we compared AQP8 localization with the localization of smooth muscle actin, a myoepithelial marker. We found that AQP8 and smooth muscle actin colocalized in both the rat SMG and PG, providing additional strong support for a myoepithelial localization of AQP8. Thus, in agreement with an earlier report by other investigators (Elkjaer et al., Am J Physiol Renal Physiol 281:F1047-F1057, 2001), we report that AQP8 is expressed in the myoepithelial cells, but not in the acinar cells, of both the rat SMG and PG.

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“…AQP2 is localized on the basolateral membrane in addition to the apical membrane of the connecting tubule and inner medullary collecting duct cells (Christensen et al, 2003), although its functional importance for transepithelial water transfer remains unknown because the basolateral membrane of these cells bears other AQP isoforms such as AQP3 and/ or AQP4 (Matsuzaki et al, 2002;Takata et al, 2005). We revealed that Ser269-phosphorylated AQP2 was also weakly detected on the basolateral membrane of these cells, in which its restricted accumulation on the apical membrane was reported by Moeller et al (2009).…”

Section: Ser269-phosphorylated Aqp2 Is Found On the Basolateral Membrmentioning

confidence: 51%

<b>Phosphorylation and dephosphorylation of aquaporin-2 at serine 269 and its subcellular distribution during vasopressin-induced exocytosis and subsequent endocytosis in the rat </b><b>kidney </b>

Shimizu

Sano

Kita

et al. 2017

Archives of Histology and Cytology

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Summary. Aquaporin-2 (AQP2) is a water channel protein that is trafficked between intracellular vesiclesand the plasma membrane of kidney collecting duct cells upon vasopressin stimulation. Vasopressin changes the phosphorylation states of the AQP2 C-terminal serines (Sers), Ser256, Ser261, Ser264, and Ser269, in rats and mice, which is thought to play a role in controlling trafficking. Here, we focused on Ser269. We developed a specific antibody to Ser269-phosphorylated AQP2. Using immunofluorescence microscopy, we examined its localization in the rat kidney following injection of vasopressin and a vasopressin type 2 receptor-specific antagonist (OPC-31260). Ser269-phosphorylated AQP2 was almost undetectable in the water-loaded rat kidney, but was detected intracellularly soon after vasopressin injection, and then highly accumulated on the apical membrane of connecting tubule and collecting duct principal cells. In addition to the apical membrane, Ser269-phosphorylated AQP2 was also detected on the basolateral membrane of connecting tubule cells and inner medullary collecting duct principal cells. OPC-31260 injection following vasopressin stimulation caused internalization of AQP2, a pool of which was phosphorylated at Ser269. These results suggest that 1) AQP2 is phosphorylated at Ser269 intracellularly upon vasopressin stimulation and is rapidly trafficked to the plasma membrane, and 2) AQP2 can be internalized from the plasma membrane even if it remains phosphorylated at Ser269.

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Aquaporin Water Channels in the Kidney

Cited by 11 publications

References 69 publications

Regulation of Aquaporins by Vasopressin in the Kidney

Regulation of Aquaporins by Vasopressin in the Kidney

Further evidence for AQP8 expression in the myoepithelium of rat submandibular and parotid glands

<b>Phosphorylation and dephosphorylation of aquaporin-2 at serine 269 and its subcellular distribution during vasopressin-induced exocytosis and subsequent endocytosis in the rat </b><b>kidney </b>

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