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SKK4, a novel activator of stress‐activated protein kinase‐1 (SAPK1/JNK)
Author(s) -
Lawler Sean,
Cuenda Ana,
Goedert Michel,
Cohen Philip
Publication year - 1997
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(97)00990-3
Subject(s) - activator (genetics) , chemistry , ask1 , microbiology and biotechnology , kinase , map kinase kinase kinase , protein kinase a , mitogen activated protein kinase kinase , biochemistry , biology , receptor
A cDNA was cloned and expressed that encodes human stress‐activated protein kinase kinase‐4 (SKK4), a novel MAP kinase kinase family member whose mRNA is widely expressed in human tissues. SKK4 activated SAPK1/JNK in vitro, but not SAPK2a/p38, SAPK2b/p38β, SAPK3/ERK6 or SAPK4. It appears to be the mammalian homologue of HEP, an activator of SAPK1/JNK in Drosophila . In human epithelial KB cells SKK4 and SKK1/MKK4 (another activator of SAPK1/JNK) were both activated by stressful stimuli, but only SKK4 was activated by proinflammatory cytokines. The identification of SKK4 explains why the major SAPK1/JNK activator detected in many mammalian cell extracts is chromatographically separable from SKK1/MKK4.