Inhibition of volume-stimulated taurine efflux and tyrosine kinase activity in the skate red blood cell

Abstract

Phosphorylation of the band 3 anion exchange protein by the tyrosine kinases p72syk and p56lyn is thought to play a role in the pathway that regulates swelling-activated taurine efflux from the skate red blood cell. In this study, the protein tyrosine kinase (PTK) inhibitors piceatannol and tyrphostin A23 both inhibited taurine efflux and the activities of the tyrosine kinases p72syk and p56lyn in the skate erythrocyte. However, the PTK inhibitors genistein and tyrphostin A46 had only small effects on taurine efflux and PTK activities. In general, a strong correlation between the extent of inhibition of taurine efflux and of tyrosine kinase activity was observed. PTK inhibitors showed a similar pattern of inhibition of band 3 phosphorylation, with the greatest inhibition observed in cells treated with piceatannol. The protein kinase C inhibitors staurosporine and bisindolylmaleimide tested alone or in combination with piceatannol had little or no significant effect on swelling-activated taurine efflux. Overall the results support the hypothesis that phosphorylation of the skate band 3 protein by p72syk and p56lyn contributes to the regulation of volume-activated taurine efflux in skate red cells, and suggest that protein kinase C may not be involved in this regulation.

Potentiation of the osmosensitive taurine release and cell volume regulation by cytosolic Ca2+ rise in cultured cerebellar astrocytes

“…The present results stress the importance of tyrosine kinases and of the tyrosine kinase target PI3K, as shown by the marked influence on taurine release of manipulating the tyrosine kinase phosphorylation state. This role of tyrosine kinases on OTR has also been observed in cerebellar granule neurons (Morales-Mulia et al, 2001), fibroblasts (Pedersen et al, 2002), glial cells of the supraoptic nucleus (Deleuze et al, 2000), and in skate and trout red cells (Musch et al, 1999;Hubert et al, 2000;Kiessling et al, 2000). The identity and hierarchy of the kinases involved is so far largely unknown except in skate red cells, where the role of the src-like kinases p56lyn and p72syk on taurine release through the anion exchanger band 3 is well documented (Musch et al, 1999;Hubert et al, 2000).…”

Signalling pathways involved in the control of sperm cell volume

“…Similar swelling-dependent activation of these channels has been demonstrated for spermatozoa of a variety of species, such as cattle, swine, human and dog (Kulkarni et al 1997, Yeung et al 2003, Petrunkina et al 2001a. In somatic cells, RVD mediated by chloride and potassium currents is known to involve signalling cascades mediated by protein phosphorylation and dephosphorylation (Klein et al 1993, Bize & Dunham 1994, Robson & Hunter 1994, Crepel et al 1998, Musch et al 1998, Voets et al 1998, Thoroed et al 1999, Hubert et al 2000. In contrast, very little is known about whether phosphorylation processes are linked to the activation of osmo-sensing regulatory mechanisms in spermatozoa.…”

Amino Acid Osmolytes in Regulatory Volume Decrease and Isovolumetric Regulation in Brain Cells: Contribution and Mechanisms

“…Swelling-induced activation of p56lck in lymphocytes is required for VSCC functioning as p56lck deficiency by genetic knockout, leads to defective VSCC and RVD, a condition reversed by retransfection of the protein [39]. Swelling-induced tyrosine phosphorylation of band 3 (anion exchanger) in skate erythrocytes is also linked to p72 syk and p56 lyn [42]. This is the first report showing direct tyrosine phosphorylation of the osmolyte translocation pathway.…”