Involvement of Aquaporin-5 Water Channel in Osmoregulation in Parotid Secretory Granules

Matsuki, Miwako; Hashimoto, Sadamitsu; Shimono, Masaki; Murakami, Masataka; Fujita-Yoshigaki, Junko; Furuyama, Shunsuke; Saito, Hiroshi

doi:10.1007/s00232-005-0736-9

Cited by 45 publications

(41 citation statements)

References 36 publications

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“…While several AQPs have been localized to intracellular vesicles, including AQP1 (Cho et al, 2002), AQP5 (Matsuki et al, 2005), AQP6 (Yasui et al, 1999), AQP10 (Li et al, 2005) and AQP12 (Itoh et al, 2005), there is no evidence of either AQP3 or AQP4 in vesicle membranes. The detection of these two AQPs in the slime gland may indicate their role in vesicle rupture, but we acknowledge that the slime gland contains several cell types, including an epithelial cell layer.…”

Section: Sus Scrofa Aqp6 [Acc66198]mentioning

confidence: 99%

“…AQPs have been found in secretory vesicles, and are thought to assist vesicle swelling and product release in many cases such as secretory vesicles in human small intestine (Li et al, 2005), rat parotid gland secretory vesicles (Matsuki et al, 2005) and zymogen granules of pancreatic acinar cells (Cho et al, 2002;Itoh et al, 2005). While several AQPs have been localized to intracellular vesicles, including AQP1 (Cho et al, 2002), AQP5 (Matsuki et al, 2005), AQP6 (Yasui et al, 1999), AQP10 (Li et al, 2005) and AQP12 (Itoh et al, 2005), there is no evidence of either AQP3 or AQP4 in vesicle membranes.…”

Section: Sus Scrofa Aqp6 [Acc66198]mentioning

confidence: 99%

“…However, a more recent study of AQP4 suggests that the Hg 2+ -sensitive domain of AQP4 is located intracellularly and is inaccessible to impermeable Hg 2+ (Yukutake et al, 2008). While the amino and carboxy termini of AQPs typically face the cytoplasm (Verkman and Mitra, 2000), the orientation of these domains in intracellular vesicle membranes can be intravesicular (Cho et al, 2002) or extravesicular (Matsuki et al, 2005). Thus it is possible that AQP4 is Hg 2+ -sensitive in hagfish slime mucin vesicles, as we do not know the orientation of AQPs in hagfish mucin vesicle membranes.…”

Section: Sus Scrofa Aqp6 [Acc66198]mentioning

confidence: 99%

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Defensive slime formation in Pacific hagfish requires Ca2+ and aquaporin mediated swelling of released mucin vesicles

Herr

Clifford

Goss

et al. 2014

Journal of Experimental Biology

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Hagfishes defend themselves from fish predators via the rapid deployment of a fibrous slime that adheres to and clogs gills. The slime transforms from a thick glandular exudate to a fully hydrated product in a fraction of a second through a process that involves the swelling and rupture of numerous mucin vesicles. Here we demonstrate that the vesicle membrane plays an important role in regulating the swelling of mucin granules, and provide evidence that the membrane contains proteins that facilitate the movement of ions and water molecules. By exposing isolated mucin vesicles to varying combinations of inorganic ions, organic compounds and membrane channel inhibitors, we found that the majority of hagfish mucin vesicles require Ca 2+ to rupture. We also show that Ca 2+-dependent rupture can be pharmacologically inhibited, which suggests a role for Ca 2+ -activated membrane transporters. We demonstrate that the aquaporin inhibitor mercuric chloride reduces the rate of vesicle swelling by an order of magnitude, which suggests that aquaporins facilitate the influx of water during vesicle deployment. Molecular evidence of two aquaporin homologues expressed in the slime glands further supports this idea. We propose a model of hagfish slime mucin vesicle rupture that involves Ca 2+ -activated transporters and aquaporins, and suggest that the presence of these proteins is an adaptation for increasing the speed of vesicle rupture and, consequently, the speed of the sliming response of hagfishes.

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Section: Sus Scrofa Aqp6 [Acc66198]mentioning

confidence: 99%

Section: Sus Scrofa Aqp6 [Acc66198]mentioning

confidence: 99%

Section: Sus Scrofa Aqp6 [Acc66198]mentioning

confidence: 99%

See 1 more Smart Citation

Defensive slime formation in Pacific hagfish requires Ca2+ and aquaporin mediated swelling of released mucin vesicles

Herr

Clifford

Goss

et al. 2014

Journal of Experimental Biology

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“…For example, AQP5 is expressed in the APM, the lateral membrane, and intracellular organelles, but not in the basilar membrane of salivary gland cells (20,21). AQP5 is also present in zymogen granules in rat parotid glands (22). AQP5 mRNA is abundantly present in rat serous acinar cells of exocrine glands such as the parotid and submandibular glands, lacrimal glands, and subepithelial glands of the upper airway, and eye, but not in kidney, brain, or intestine (23).…”

Section: Aquaporin Water Channel Proteins In Salivary Glandsmentioning

confidence: 99%

Water Channels and Zymogen Granules in Salivary Glands

et al. 2006

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Abstract. Salivary secretion occurs in response to stimulation by neurotransmitters released from autonomic nerve endings. The molecular mechanisms underlying the secretion of water, a main component of saliva, from salivary glands are not known; the plasma membrane is a major barrier to water transport. A 28-kDa integral membrane protein, distributed in highly waterpermeable tissues, was identified as a water channel protein, aquaporin (AQP). Thirteen AQPs (AQP0 -AQP12) have been identified in mammals. AQP5 is localized in lipid rafts under unstimulated conditions and translocates to the apical plasma membrane in rat parotid glands upon stimulation by muscarinic agonists. The importance of increases in intracellular calcium concentration [Ca 2+ ] i and the nitric oxide synthase and protein kinase G signaling pathway in the translocation of AQP5 is reviewed in section I. Signals generated by the activation of Ca 2+ mobilizing receptors simultaneously trigger and regulate exocytosis. Zymogen granule exocytosis occurs under the control of essential process, stimulus-secretion coupling, in salivary glands. Ca 2+ signaling is a principal signal in both protein and water secretion from salivary glands induced by cholinergic stimulation. On the other hand, the cyclic adenosine monophosphate (cAMP)/ cAMP-dependent protein kinase system has a major role in zymogen granule exocytosis without significant increases in [Ca 2+ ] i . In section II, the mechanisms underlying the control of salivary protein secretion and its dysfunction are reviewed.

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“…AQP8 may be a genuine ZG membrane protein, however a contamination by mitochondria cannot be ruled out, which express AQP8 as well (16,61). Swelling assays of secretory granules and immunological studies have suggested that AQP5 and AQP6 mediate osmotic swelling of isolated parotid secretory granules suspended in isoosmotic KCl solutions (72,74), but the presence of AQP5 in parotid granules has also been contested using various immunological techniques (75).…”

Section: Channels H 2 O Channelsmentioning

confidence: 99%

Channels and Transporters in Zymogen Granule Membranes and their Role in Granule Function: Recent Progress and a Critical Assessment

Thévenod

The Pancreapedia: Exocrine Pancreas Knowledge Base

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Secretory granules are located at the apex of pancreatic acinar cells. Secretagogues bind to their receptors at the basolateral membrane of acinar cells and trigger the activation of intracellular signaling pathways to elicit fusion of secretory granules with the apical plasma membrane that is followed by exocytosis of digestive pro-enzymes (the "zymogens") into the lumen. This regulated discharge of stored macromolecules is accompanied by the secretion of solutes and water to the cell exterior to hydrate these protein-rich secretory products. Previous functional and pharmacological studies in pancreatic acinar cells and zymogen granules (ZG) had suggested that ion channels and transporters are expressed in the membrane of ZG where they contribute to maturation, fusion, exocytosis and/or fluidization of zymogens. This chapter reviews studies that have been largely published in the postgenomic era and combined biochemical, immunological, electrophysiological, pharmacological, and/or occasionally knockout methodologies to identify cloned transporters and ion channels in the membrane of ZG. Available experimental evidence indicates the presence of several ion channel and transporter proteins in ZG membranes (aquaporins, vacuolar-type H + -ATPase, zinc influx transporter SLC30A2). The evidence for the K + channels Kv7.1 and Kir6.1, for ClC Cl -channels and the vesicular nucleotide transporter SLC17A9 in ZG is less strong. To better understand the function of these proteins in the secretory pathway further studies are needed. Introductory RemarksA review on the topic of pancreatic zymogen granule (ZG) channels and transporters and their function is timely as the last exhaustive review appeared in 2002 (107) and is manageable because of the limited number of publications that had been published in the 12 years since then. These circumstances have allowed me to carry out an in-depth and critical analysis of the published data. The advent of the post-genomic era had raised hopes that -similar to other areas of cell biology -a large number of ZG transport proteins would be identified and their role in pancreatic secretion would be elucidated. Indeed, recent studies have combined functional and molecular approaches to characterize ZG channels and transporters and their role in pancreas physiology. Yet, the fact that only a very limited number of studies have been published in this area of research is surprising as there have been tremendous developments of knowledge and methodologies available to investigate the molecular and cellular biology and physiology of the pancreas (122).

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Involvement of Aquaporin-5 Water Channel in Osmoregulation in Parotid Secretory Granules

Cited by 45 publications

References 36 publications

Defensive slime formation in Pacific hagfish requires Ca2+ and aquaporin mediated swelling of released mucin vesicles

Defensive slime formation in Pacific hagfish requires Ca2+ and aquaporin mediated swelling of released mucin vesicles

Water Channels and Zymogen Granules in Salivary Glands

Channels and Transporters in Zymogen Granule Membranes and their Role in Granule Function: Recent Progress and a Critical Assessment

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