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MAPKp38 a signal transduction component of heavy metals induced Phytochelatins accumulation
Author(s) -
TorresMarquez M Eugenia,
Rios D,
Vega MA,
Rodriguez JS,
Garcia J
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a985-d
Subject(s) - chemistry , in vitro , signal transduction , activator (genetics) , cell culture , euglena gracilis , kinetics , microbiology and biotechnology , biochemistry , biophysics , biology , receptor , genetics , gene , physics , chloroplast , quantum mechanics
Euglena gracilis is able to endure high concentrations of heavy metals (HM), even more when they are continuously exposed to 1.5μM Hg 2+ (pre‐Hg). Phytochelatins (PhC) are involved in HM resistance mechanisms, as chelators. PhC accumulation stimulated by HM exposure can be observed around 48 h of culture, being higher for pre‐Hg cells in comparison to cells without previous exposure to HM (C). HM stress is an activator of MAPKp38. In an attempt to understand which transduction signals could be mediating HM stress induction of PhC accumulation, we sought whether MAPKp38 activation participates on such pathway. We have found in a time‐course for PhC, 24–52 h E. gracilis culture, that they have a cyclic kinetics of accumulation, and that Pre‐Hg cells start up with a higher level (2 fold) of PhC. When cells are presented to a 200 μM Cd 2+ challenge, an increase of PhC is observed peaking at 35 h of culture, with higher levels for pre‐Hg. Participation of MAPKp38 was tested by adding its inhibitor SB203598 at 24 h and looking for PhC accumulation at 35 h. We found that SB203590 inhibits Cd 2+ stimulated PhC accumulation, with a more potent effect on C‐Cd 2+ stimulated cells. In vitro activity assays of MAPKp38 from those 35 h cultured cells, treated with or without Cd 2+ , showed that basal activity is already higher in pre‐Hg cells compared to C cells, and that Cd 2+ strongly induces activation on C cells, while pre‐Hg responded to a lesser extent, SB203598 treated cells showed in situ inhibition of MAPKp38. Then, MAPKp38 could be participating on priming PhC accumulation. DGAPA‐ IN224606