Tyrosine phosphorylation modulates the osmosensitivity of volume‐dependent taurine efflux from glial cells in the rat supraoptic nucleus

Deleuze, Charlotte; Duvoid, A.; Moos, Françoise; Hussy, Nicolas

doi:10.1111/j.1469-7793.2000.t01-2-00291.x

Cited by 50 publications

(41 citation statements)

References 50 publications

(100 reference statements)

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“…In Intestine 407 cells, however, in clear contrast to the activation of VRAC (53,55), the release of taurine was found to be independent of tyrosine kinases and PtdIns 3-kinase and did not involve p21 rho . A similar low sensitivity to genistein has been reported for isolated rat supraoptic astrocytes (6). Taken together, these results indicate not only that the release of taurine does not involve VRAC in intestine 407 cells but also that distinct signaling pathways are involved in the regulation of Cl Ϫ and taurine efflux (54).…”

Section: Discussionsupporting

confidence: 57%

Osmotic swelling-provoked release of organic osmolytes in human intestinal epithelial cells

Tomassen¹,

Fekkes²,

Jonge³

et al. 2004

American Journal of Physiology-Cell Physiology

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Human Intestine 407 cells respond to osmotic cell swelling by the activation of Cl−- and K+-selective ionic channels, as well as by stimulating an organic osmolyte release pathway readily permeable to taurine and phosphocholine. Unlike the activation of volume-regulated anion channels (VRAC), activation of the organic osmolyte release pathway shows a lag time of ∼30–60 s, and its activity persists for at least 8–12 min. In contrast to VRAC activation, stimulation of organic osmolyte release did not require protein tyrosine phosphorylation, active p21rho, or phosphatidylinositol 3-kinase activity and was insensitive to Cl− channel blockers. Treatment of the cells with putative organic anion transporter inhibitors reduced the release of taurine only partially or was found to be ineffective. The efflux was blocked by a subclass of organic cation transporter (OCT) inhibitors (cyanine-863 and decynium-22) but not by other OCT inhibitors (cimetidine, quinine, and verapamil). Brief treatment of the cells with phorbol esters potentiated the cell swelling-induced taurine efflux, whereas addition of the protein kinase C (PKC) inhibitor GF109203X largely inhibited the response, suggesting that PKC is involved. Increasing the level of intracellular Ca2+ by using A-23187- or Ca2+-mobilizing hormones, however, did not affect the magnitude of the response. Taken together, the results indicate that the hypotonicity-induced efflux of organic osmolytes is independent of VRAC and involves a PKC-dependent step.

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Section: Discussionsupporting

confidence: 57%

Osmotic swelling-provoked release of organic osmolytes in human intestinal epithelial cells

Tomassen¹,

Fekkes²,

Jonge³

et al. 2004

American Journal of Physiology-Cell Physiology

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“…In cell culture models, tyrosine kinase activity is up-regulated by hypotonic stress (9, 10) and is required for immediate-early gene transcription and expression (10,32). Pharmacological inhibition of tyrosine kinase activity blocks, and potentiation of tyrosine kinase activity inhibits, regulatory volume decreaseassociated efflux of cations (9), chloride (33)(34)(35)(36)(37)(38)(39), and the amino acid osmolyte, taurine (39,40).…”

Section: Discussionmentioning

confidence: 99%

Regulation of a Transient Receptor Potential (TRP) Channel by Tyrosine Phosphorylation

Xu¹,

Zhao²,

Tian³

et al. 2003

Journal of Biological Chemistry

177

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The recently identified transient receptor potential (TRP) channel family member, TRPV4 (formerly known as OTRPC4, VR-OAC, TRP12, and VRL-2) is activated by hypotonicity. It is highly expressed in the kidney as well as blood-brain barrier-deficient hypothalamic nuclei responsible for systemic osmosensing. Apart from its gating by hypotonicity, little is known about TRPV4 regulation. We observed that hypotonic stress resulted in rapid tyrosine phosphorylation of TRPV4 in a heterologous expression model and in native murine distal convoluted tubule cells in culture. This tyrosine phosphorylation was sensitive to the inhibitor of Src family tyrosine kinases, PP1, in a dose-dependent fashion. TRPV4 associated with Src family kinases by co-immunoprecipitation studies and confocal immunofluorescence microscopy, and this interaction required an intact Src family kinase SH2 domain. One of these kinases, Lyn, was activated by hypotonic stress and phosphorylated TRPV4 in an immune complex kinase assay and an in vitro kinase assay using recombinant Lyn and TRPV4. Transfection of wild-type Lyn dramatically potentiated hypotonicity-dependent TRPV4 tyrosine phosphorylation whereas dominant negative-acting Lyn modestly inhibited it. Through mutagenesis studies, the site of tonicity-dependent tyrosine phosphorylation was mapped to Tyr-253, which is conserved across all species from which TRPV4 has been cloned. Importantly, point mutation of Tyr-253 abolished hypotonicity-dependent channel activity. In aggregate, these data indicate that hypotonic stress results in Src family tyrosine kinasedependent tyrosine phosphorylation of the tonicity sensor TRPV4 at residue Tyr-253 and that this residue is essential for channel function in this context. This is the first example of direct regulation of TRP channel function through tyrosine phosphorylation.Signaling by hypotonic stress and cell swelling has been well studied in diverse models (reviewed in Ref. 1). Nonetheless, the sensor for hypotonic stress, both at the single cell and organismal levels, remains elusive. A member of the transient receptor potential (TRP) 1 family of cation channels has recently been described that fulfills multiple criteria for an osmosensing protein. Based upon homology with OSM-9, an osmosensing TRPlike channel expressed in Caenorhabditis elegans (2), the mammalian candidate osmosensing TRP channel family member, was cloned independently as OTRPC4 (3) and VR-OAC (4). This protein, also identified as TRP12 and vanilloid receptorrelated protein-2 in other contexts, was recently renamed TRPV4 (5).TRPV4, as a member of the TRPV subfamily of TRP channels, shares close homology with the following channels: 1) the vanilloid (capsaicin) receptor and sensor of noxious heat, TRPV1; 2) the heat-sensitive vanilloid receptor-related channel-1, TRPV2; 3) the calcium channels, TRPV5 (formerly known as ECaC1 and CaT2) and TRPV6 (formerly known as CaT1, ECaC2, and CaT-L) (all reviewed in Ref. 5 and references therein); and 4) the very recently described temperaturesensi...

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“…An alternative explanation for the effect of kinase inhibitors on isotonic volume in spermatozoa might have been that they caused enhancement of taurine flux (e.g. in glial cells; Deleuze et al 2000); however, it has recently been shown that taurine efflux is not essentially involved in volume control in boar or human spermatozoa, although it does play a role in mouse sperm RVD (Yeung et al 2003, Petrunkina et al 2004a. While staurosporine, lavendustin and Bis I led to comparable increases in isotonic volume, the effect of the PKC inhibitor Bis X was less.…”

Section: Discussionmentioning

confidence: 99%

Signalling pathways involved in the control of sperm cell volume

Petrunkina¹,

Harrison²,

Tsolova³

et al. 2007

Reproduction

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The ability to maintain cellular volume is an important general physiological function, which is achieved by specific molecular mechanisms. Hypotonically induced swelling results in the opening of K C and Cl K ion channels, through which these ions exit with accompanying water loss. This process is known as regulatory volume decrease (RVD). The molecular mechanisms that control the opening of the ion channels in spermatozoa are as yet poorly understood. The present study investigated pathways of osmo-signalling using boar spermatozoa as a model. Spermatozoa were diluted into isotonic and hypotonic Hepes-buffered saline in the presence or absence of effector drugs, and at predetermined intervals volume measurements were performed electronically. Treatment with protein kinase C (PKC) inhibitors staurosporine, bismaleimide I and bismaleimide X led to dosedependent increases of both isotonic and hypotonic volumes (P!0.05). However, as the isotonic volume was affected more than the hypotonic volume, the kinase inhibitors appeared to improve RVD, whereas activation of PKC with phorbol dibutyrate blocked RVD. The increase in isotonic cell volume induced by bismaleimide X was observed in chloride-containing medium but not in the medium in which chloride was replaced by sulphate, implying that PKC was involved in the control of chloride channel activity, e.g. by closing the channel after volume adjustment. The protein phosphatase PP1/PP2 inhibitors calyculin and okadaic acid increased the isotonic volume only slightly but they greatly increased the relative cell volume and blocked RVD. The activation of RVD processes was found to be cAMP-dependent; incubation with forskolin and papaverine improved volume regulation. Moreover, papaverine was able to overcome the negative effect of protein phosphatase inhibitors. The mechanism of sperm RVD appears to involve (a) alterations in protein phosphorylation/dephosphorylation balance brought about by PKC and PP1 and (b) a cAMP-dependent activating pathway.

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Tyrosine phosphorylation modulates the osmosensitivity of volume‐dependent taurine efflux from glial cells in the rat supraoptic nucleus

Cited by 50 publications

References 50 publications

Osmotic swelling-provoked release of organic osmolytes in human intestinal epithelial cells

Osmotic swelling-provoked release of organic osmolytes in human intestinal epithelial cells

Regulation of a Transient Receptor Potential (TRP) Channel by Tyrosine Phosphorylation

Signalling pathways involved in the control of sperm cell volume

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