Cooperation of Tyrosine Kinases P72^syk and P53/56^lyn Regulates Calcium Mobilization in Chicken B Cell Oxidant Stress Signaling

Abstract

A chicken B cell line DT40 and its syk-negative or lyn-negative mutants were used to investigate the roles of protein-tyrosine kinases in oxidant $tress signaling. The data presented here for wild-type cells demonstrate that hydrogen peroxide stimulates p53/56""-dependent tyrosine phosphorylation and activation of ~7 2 "~, and induces a rapid and prolonged elevation of intracellular calcium, which consists of calcium release from intracellular stores and influx from the extracellular space. Hydrogen-peroxidetriggered calcium mobilization was impaired in both syk-negative and lyn-negative cells, which was mainly due to the loss of calcium release from intracellular stores. Further studies indicated that inositol trisphosphate production was also abolished in both syk-negative and lyn-negative cells, which is consistent with the loss of calcium release. Taken together, these observations suggest that the defect of ~7 2 " " or p53/56"" was responsible for the abnormality of calcium mobilization in both Zyn-negative and syknegative cells, and that both ~7 2 " '~ and p53/56'"' might regulate calcium mobilization through the phosphatidylinositol pathway in B cell oxidant stress signaling.

A respiratory chain controlled signal transduction cascade in the mitochondrial intermembrane space mediates hydrogen peroxide signaling

“…Of note, the cellular models used in this study were remarkably resistant to the effects of H 2 O 2 in our hands, consistent with some previous results (47,48 tyrosine phosphorylation of Syk pathway members Lyn, Syk, SHP1, Btk, and PLCγ2, as well as of many other proteins (Fig. 1D and Fig.…”

Interference of H2O2 with stimulus‐secretion coupling in mouse pancreatic β‐cells

“…An elevation of [Ca¥]é induced by HµOµ has been observed in a variety of other cells such as smooth muscle cells (Roveri et al 1992;Krippeit-Drews et al 1995), endothelial cells (Doan et al 1994), mesangial cells (Shaw et al 1995;Meyer et al 1996), a B-cell line (Qin et al 1996), neuronal cells (Whittemore et al 1995), myocytes (Nakamura et al 1993) and renal tubular cells (Ueda & Shah, 1992), and the effect has been associated with HµOµ-induced cell injury in, for example, renal tubular cells (Ueda & Shah, 1992), myocytes (Nakamura et al 1993), glomerular mesangial cells (Shaw et al 1995) and neuronal cells (Whittemore et al 1995). The augmentation of [Ca¥]é has been attributed to influx across the plasma membrane (Meyer et al 1996), to mobilization from intracellular stores (Ueda & Shah, 1992) or to both mechanisms (Roveri et al 1992;Doan et al 1994;KrippeitDrews et al 1995;Shaw et al 1995;Qin et al 1996). The observation that HµOµ decreased the ATP concentration raises the question of whether HµOµ also influences an ATP-dependent step in stimulus-secretion coupling distal to the membrane potential.…”

Suofu Qin’s work on studies of cell survival signaling in cancer and epithelial cells

“…Syk activation plays a protective role in mediating osmotic stress / ceramide-induced apoptosis [22,25] . Oxidative stress elicits an increase in [Ca 2+ ]i by stimulating both an extracellular Ca 2+ influx and Ca 2+ release from internal stores in DT40 cells [18,20] . Oxidative stressstimulated calcium release from intracellular stores is achieved through the activation of phospholipase Cγ2 (PLCγ2) via a tyrosine phosphorylation mechanism, but this Ca 2+ response is partially abolished in Syk-deficient cells [18,20] , suggesting that other molecules work in concert with Syk in mediating oxidative stress-induced calcium release.…”

“…Oxidative stress elicits an increase in [Ca 2+ ]i by stimulating both an extracellular Ca 2+ influx and Ca 2+ release from internal stores in DT40 cells [18,20] . Oxidative stressstimulated calcium release from intracellular stores is achieved through the activation of phospholipase Cγ2 (PLCγ2) via a tyrosine phosphorylation mechanism, but this Ca 2+ response is partially abolished in Syk-deficient cells [18,20] , suggesting that other molecules work in concert with Syk in mediating oxidative stress-induced calcium release. To this end, Bruton's tyrosine kinase (Btk), one of Tec-family non-receptor tyrosine kinase with one pleckstrin homology (PH) domain targeting proteins to where phosphatidylinositol 3,4,5-trisphosphate is produced, is activated by oxidative stress [28,29] .…”

“…Mutagenesis study reveals that Syk activation is the combined effects of autophosphorylation and phosphorylation by other tyrosine kinases [19] . The initiating tyrosine kinase for Syk activation is Lyn, member of Src family protein tyrosine kinase in DT40 cells [20] . Moreover, mSH2(N) Syk, but not mSH2(C) Syk, in which the phosphotyrosine-dependent binding motif within the SH2 domains is mutated, showed a significantly higher activity than that observed in wild-type Syk, indicating that SH2(N) suppress Syk activity and SH2(N) and SH2(C) of Syk play distinctive functions in oxidative stress signaling [19,21] .…”