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GADD45β/GADD45γ and MEKK4 comprise a genetic pathway mediating STAT4‐independent IFNγ production in T cells
Author(s) -
Chi Hongbo,
Lu Binfeng,
Takekawa Mutsuhiro,
Davis Roger J,
Flavell Richard A
Publication year - 2004
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600173
Subject(s) - biology , genetics , gadd45 , stat4 , gene , microbiology and biotechnology , stat , cell cycle , stat3 , cell cycle checkpoint
The stress‐inducible molecules GADD45β and GADD45γ have been implicated in regulating IFNγ production in CD4 T cells. However, how GADD45 proteins function has been controversial. MEKK4 is a MAP kinase kinase kinase that interacts with GADD45 in vitro . Here we generated MEKK4‐deficient mice to define the function and regulation of this pathway. CD4 T cells from MEKK4−/− mice have reduced p38 activity and defective IFNγ synthesis. Expression of GADD45β or GADD45γ promotes IFNγ production in MEKK4+/+ T cells, but not in MEKK4−/− cells or in cells treated with a p38 inhibitor. Thus, MEKK4 mediates the action of GADD45β and GADD45γ on p38 activation and IFNγ production. During Th1 differentiation, the GADD45β/GADD45γ/MEKK4 pathway appears to integrate upstream signals transduced by both T cell receptor and IL12/STAT4, leading to augmented IFNγ production in a process independent of STAT4.