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A heat‐activated MAP kinase (HAMK) as a mediator of heat shock response in tobacco cells
Author(s) -
SURI SARABJEET S.,
DHINDSA RAJINDER S.
Publication year - 2008
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2007.01754.x
Subject(s) - microbiology and biotechnology , kinase , heat shock protein , heat shock , protein kinase a , mitogen activated protein kinase , mapk/erk pathway , hsf1 , chemistry , extracellular , hsp70 , biology , biochemistry , gene
A heat‐activated MAP kinase (HAMK), immunologically related to the extracellular signal‐regulated kinase (ERK) super‐family of protein kinases, has been identified in BY2 cells of tobacco. The activation of HAMK at 37 °C was transient and detected within 2 min and reached a maximum level within 5 min. Ca 2+ chelators and channel blockers, and the known inhibitors of MEK, a MAP kinase kinase, prevented the heat activation of HAMK. This suggests that HAMK activation is part of a heat‐triggered MAP kinase cascade that requires Ca 2+ influx. The heat shock protein HSP70 accumulated at 37 °C, but not when HAMK activation was prevented with the inhibitors of MEK or with Ca 2+ chelators or channel blockers. As previously shown for heat activation of HAMK, heat‐induced accumulation of HSP70 requires membrane fluidization and reorganization of cytoskeleton. We concluded that heat‐triggered HAMK cascade might play an essential role in the launching of heat shock response and hsp gene expression in tobacco cells.