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In vivo and in vitro activation of temperature‐responsive plant map kinases
Author(s) -
Sangwan Veena,
Dhindsa Rajinder S
Publication year - 2002
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(02)03626-8
Subject(s) - kinase , mitogen activated protein kinase , microbiology and biotechnology , in vitro , in vivo , chemistry , biophysics , heat shock , heat shock protein , biochemistry , biology , genetics , gene
Alfalfa cells possess two temperature‐responsive Mitogen‐Activated Protein Kinases (MAPKs), SAMK (Stress‐Activated MAP Kinase) activated at 4°C and HAMK (Heat shock‐Activated MAP Kinase) activated at 37°C. Both are inactive at 25°C. We show here that SAMK is activated when cells are transferred from 37°C to 25°C, and HAMK is activated when cells are transferred from 4°C to 25°C. Moreover, we show that heat activation of HAMK also occurs in cell‐free extracts. We conclude that (i) SAMK or HAMK activation does not require a particular temperature but a relative temperature shift, and (ii) that either HAMK itself or one or more of its upstream activators can sense temperature change directly.