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Distinct carboxy‐termini confer divergent characteristics to the mitogen‐activated protein kinase p38α and its splice isoform Mxi2
Author(s) -
Sanz Victoria,
Arozarena Imanol,
Crespo Piero
Publication year - 2000
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(00)01598-2
Subject(s) - gene isoform , kinase , alternative splicing , p38 mitogen activated protein kinases , mitogen activated protein kinase , phosphatase , protein kinase a , splice , microbiology and biotechnology , biology , biochemistry , chemistry , phosphorylation , gene
The p38 family of mitogen‐activated protein kinases is composed of several isoforms. Mxi2 is a splicing variant of p38α that harbors a unique carboxy‐terminus. Here we show that this sole divergence results in remarkable differences between Mxi2 and p38α. Mxi2 is distinctively activated by stress stimuli and potently activated by mitogens. Mxi2 affinity for bona fide p38 substrates is remarkably diminished and Mxi2 activity is largely unaffected by the phosphatase CL100. Also, Mxi2 sensitivity to inhibition by SB203580 is greatly reduced. Interestingly, we show that the p38 C‐terminus is involved in conferring sensitivity to this compound. Overall, our results point to the p38 carboxy‐terminus as a key determinant of the biochemical properties of this family of kinases.