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ABSTRACT: Background
The tristetraprolin (TTP) family of mRNA-binding proteins contains three major members, Ttp, Zfp36l1, and Zfp36l2. Ttp down-regulates the stability of AU-rich element-containing mRNAs and functions as an anti-inflammation regulator.Methods
To examine whether other TTP family proteins also play roles in the inflammatory response, their expression profiles and the possible mRNA targets were determined in the knockdown cells.Results
Ttp mRNA and protein were highly induced by lipopolysaccharide (LPS), whereas Zfp36l1 and Zfp36l2 mRNAs were down-regulated and their proteins were phosphorylated during early lipopolysaccharide stimulation. Biochemical and functional analyses exhibited that the decrease of Zfp36l2 mRNA was cross-regulated by Ttp. Knockdown of Zfp36l1 and Zfp36l2 increased the basal level of Mkp-1 mRNAs by prolonging its half-life. Increasing the expression of Mkp-1 inhibited the activation of p38 MAPK under lipopolysaccharide stimulation and down-regulated Tnfα, and Ttp mRNA. In addition, hyper-phosphorylation of Zfp36l1 might stabilize Mkp-1 expression by forming a complex with the adapter protein 14-3-3 and decreasing the interaction with deadenylase Caf1a.Conclusions
Our findings imply that the expression and phosphorylation of Zfp36l1 and Zfp36l2 may modulate the basal level of Mkp-1 mRNA to control p38 MAPK activity during lipopolysaccharide stimulation, which would affect the inflammatory mediators production. Zfp36l1 and Zfp36l2 are important regulators of the innate immune response.
SUBMITTER: Wang KT
PROVIDER: S-EPMC4502546 | biostudies-literature | 2015
REPOSITORIES: biostudies-literature
Wang Kuan-Ting KT Wang Hsin-Hui HH Wu Yan-Yun YY Su Yu-Lun YL Chiang Pei-Yu PY Lin Nien-Yi NY Wang Shun-Chang SC Chang Geen-Dong GD Chang Ching-Jin CJ
Journal of inflammation (London, England) 20150716
<h4>Background</h4>The tristetraprolin (TTP) family of mRNA-binding proteins contains three major members, Ttp, Zfp36l1, and Zfp36l2. Ttp down-regulates the stability of AU-rich element-containing mRNAs and functions as an anti-inflammation regulator.<h4>Methods</h4>To examine whether other TTP family proteins also play roles in the inflammatory response, their expression profiles and the possible mRNA targets were determined in the knockdown cells.<h4>Results</h4>Ttp mRNA and protein were highl ...[more]