(American Society for Biochemistry and Molecular Biology, 2017) Hayakawa, Morisada; Hayakawa, Hiroko; Petrova, Tsvetana; Ritprajak, Patcharee; Sutavani, Ruhcha V.; Jiménez-Andrade, Guillermina Yanek; Sano, Yasuyo; Choo, Min-Kyung; Seavitt, John; Venigalla, Ram K. C.; Otsu, Kinya; Georgopoulos, Katia; Arthur, J. Simon C.; Park, Jin Mo
The evolutionarily conserved protein kinase p38 mediates innate resistance to environmental stress and microbial infection. Four p38 isoforms exist in mammals and may have been co-opted for new roles in adaptive immunity. Murine T cells deficient in p38α, the ubiquitously expressed p38 isoform, showed no readily apparent cell-autonomous defects while expressing elevated amounts of another isoform, p38β. Mice with T cells simultaneously lacking p38α and p38β displayed lymphoid atrophy and elevated Foxp3+ regulatory T cell frequencies. Double deficiency of p38α and p38β in naïve CD4+ T cells resulted in an attenuation of MAPK-activated protein kinase (MK)-dependent mTOR signaling after T cell receptor engagement, and enhanced their differentiation into regulatory T cells under appropriate inducing conditions. Pharmacological inhibition of the p38-MK-mTOR signaling module produced similar effects, revealing potential for therapeutic applications.
