Functional requirement of aquaporin-5 in plasma membranes of sweat glands

Nejsum, Lene N.; Kwon, Tae Hwan; Jensen, Uffe Birk; Fumagalli, O; Frøkiær, Jørgen; Krane, Carissa M.; Menon, Anil G.; King, Landon S.; Agre, Peter; Nielsen, Søren

doi:10.1073/pnas.012588099

Cited by 192 publications

(194 citation statements)

References 43 publications

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“…AQP1 has two consensus sequences for N-linked glycosylation at amino acids 42 and 205 (Huebert et al, 2002;Moon et al, 1995). Glycosylation has been confirmed by the deglycosylation studies conducted by Preston et al (1992) and Nejsum et al (2002); moreover, the antibody supplier's data sheet on "specificity of the antibody" has cited the binding of the antibody to glycosylated AQP1. The quantity of AQP1 protein increased steadily from P0.5 to P30.0.…”

Section: Developmental Expression Of Aqp1 Proteinmentioning

confidence: 86%

Functional expression of aquaporins in embryonic, postnatal, and adult mouse lenses

Varadaraj

Kumari

Mathias

2007

Developmental Dynamics

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Aquaporin 0 (AQP0) and AQP1 are expressed in the lens, each in a different cell type, and their functional roles are not thoroughly understood. Our previous study showed that these two AQPs function as water transporters. In order to further understand the functional significance of these two different aquaporins in the lens, we investigated their initiation and continued expression. AQP0 transcript and protein were first detected at embryonic stage (E) 11.25 in the differentiating primary fiber cells of the developing lens; its synthesis continued through the adult stage in the secondary fiber cells. Low levels of AQP1 expression were first seen in lens anterior epithelial cells at E17.5; following postnatal day (P) 6.5, the expression gradually progressed towards the equatorial epithelial cells. In the postnatal lens, the increase in membrane water permeability of epithelial cells and lens transparency coincides with the increase in AQP1 expression. AQP1 expression reaches its peak at P30 and continues through the adult stage both in the anterior and equatorial epithelial cells. The enhancement in AQP1 expression concomitant with the increase in the size of the lens suggests the progression in the establishment of the lens microcirculatory system. In vitro and in vivo studies show that both aquaporins share at least one important function, which is water transport in the lens microcirculatory system. However, the temporal expression of these two AQPs suggests an apparently unique role/s in lens development and transparency. To our knowledge, this is the first report on the expression patterns of AQP0 and AQP1 during lens development and differentiation and their relation to lens transparency. Developmental Dynamics 236:1319 -1328, 2007.

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Section: Developmental Expression Of Aqp1 Proteinmentioning

confidence: 86%

Functional expression of aquaporins in embryonic, postnatal, and adult mouse lenses

Varadaraj

Kumari

Mathias

2007

Developmental Dynamics

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“…Aquaporin-5 (AQP5) is a member of a family of water channel proteins [22,23] and is expressed at high levels in the lung, salivary gland and lacrimal tissues [1][2][3][4][5][6][7][8]. In the human, mouse and rat genome, the Aqp5 gene is located in a closely spaced tandem arrangement with Aqp2 and Aqp6 [24].…”

Section: Discussionmentioning

confidence: 99%

“…The Aqp5 gene encodes the water channel protein aquaporin-5 (AQP5) and is highly expressed in lung, salivary glands and lacrimal tissue [1][2][3][4][5][6][7][8]. In adult rat lung alveolar epithelium, AQP5 is selectively expressed on the apical surface of alveolar epithelial type I cells [2,4,5].…”

Section: Introductionmentioning

confidence: 99%

Conserved elements within first intron of aquaporin-5 (Aqp5) function as transcriptional enhancers

Flodby

Zhou

Ann

et al. 2007

Biochemical and Biophysical Research Communications

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A 4.3-kb rat aquaporin-5 (Aqp5) promoter that directs lung and salivary cell-specific expression in vitro directs low level expression of a GFP reporter in lungs of transgenic mice. Alignment of rat, mouse and human AQP5 genomic sequences identified a highly conserved region in the 3′ portion of intron 1, here termed ci1. To investigate the role of ci1 in Aqp5 expression, transient transfections were undertaken in AQP5-expressing mouse lung epithelial (MLE-15) and rat salivary (Pa-4) cells and AQP5-non-expressing NIH/3T3 cells. A 536 bp ci1 fragment enhanced transcriptional activity of the rat Aqp5 minimal promoter specifically in MLE-15 cells in an orientation-independent manner. Enhancer activity was Aqp5 promoter-specific, since no increase in activity was detected with the TK promoter. These results suggest that expression of transgenes in mouse lungs under direction of the 4.3 kb rat Aqp5 promoter may be augmented by inclusion of ci1 in transgenic constructs.

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“…Until recently, the expression of AQP5 in the skin was believed to be restricted to the sweat gland cells in the dermis, although its role in sweat secretion is not clear (Nejsum et al, 2002;Song et al, 2002;Inoue et al, 2013). However, we have recently reported the first inherited skin disease associated with aquaporin mutations and have shown that AQP5 is expressed throughout the epidermis, albeit at a much lower level than seen in the sweat glands, with a particularly strong localisation at the plasma membrane in keratinocytes of the stratum granulosum of the palmar epidermis (Fig.…”

Section: Aqp5mentioning

confidence: 99%

Defective channels lead to an impaired skin barrier

Blaydon¹,

Kelsell²

2014

Journal of Cell Science

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Channels are integral membrane proteins that form a pore, allowing the passive movement of ions or molecules across a membrane (along a gradient), either between compartments within a cell, between intracellular and extracellular environments or between adjacent cells. The ability of cells to communicate with one another and with their environment is a crucial part of the normal physiology of a tissue that allows it to carry out its function. Cell communication is particularly important during keratinocyte differentiation and formation of the skin barrier. Keratinocytes in the skin epidermis undergo a programme of apoptosis-driven terminal differentiation, whereby proliferating keratinocytes in the basal (deepest) layer of the epidermis stop proliferating, exit the basal layer and move up through the spinous and granular layers of the epidermis to form the stratum corneum, the external barrier. Genes encoding different families of channel proteins have been found to harbour mutations linked to a variety of rare inherited monogenic skin diseases. In this Commentary, we discuss how human genetic findings in aquaporin (AQP) and transient receptor potential (TRP) channels reveal different mechanisms by which these channel proteins function to ensure the proper formation and maintenance of the skin barrier.

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Functional requirement of aquaporin-5 in plasma membranes of sweat glands

Cited by 192 publications

References 43 publications

Functional expression of aquaporins in embryonic, postnatal, and adult mouse lenses

Functional expression of aquaporins in embryonic, postnatal, and adult mouse lenses

Conserved elements within first intron of aquaporin-5 (Aqp5) function as transcriptional enhancers

Defective channels lead to an impaired skin barrier

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