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c-Jun N-terminal protein kinase (c-Jun NH2-terminalprotein kinase, JNK) family of mitogen-activated protein kinase (MAPK) superfamily. JNK-center signal pathway can be activated by various factors such as cytokines, growth factors, stress. A large number of experiments confirmed that the JNK signaling pathway in cell differentiation, apoptosis, stress response as well as a variety of plays a vital role in the occurrence and development of human diseases. Nuclear orphan receptor TR3 is the product of a legislation as early genes (immediate early gene), and steroid hormone receptor structure, is one of the important members of the nuclear receptor superfamily. TR3 may be a variety of growth factor-induced expression of the apoptosis-inducing agent, with complex biological functions involved in cell proliferation, differentiation, development and apoptosis regulation process. Our laboratories previous experiments have proved, the JNK activator Anisomycin can induce TR3 phosphorylation and constructed series of TR3 deletion mutant (TR3 of △ C574, TR3 of △ N98, N50 TR3 of △ △ N74 TR3 of, TR3 of △ N84, TR3 of △ N92) speculated JNK phosphorylation of TR3 sites may be provided between the amino acid residues 93-98 (93-ATS * PAS-98), because in this sequence contains the typical pattern of JNK phosphorylation sequence S * P. In this paper, we further confirmed, Anisomycin induced TR3 phosphorylation by activating JNK1 (but not p38 and ERK), the process can be to JNK the upstream kinase MAPKK4 and MAPKK7 regulation. Upcoming TR3 by building new TR3 point mutations (95 serine mutated to alanine), we confirmed JNK phosphorylation of TR3 precise sites located TR3 95 serine. Further study showed, JNK phosphorylation TR3 and TR3 ubiquitination to closely related. The combination of phosphoric acid into ubiquitin anchor point, promote TR3, ubiquitination and degradation. In addition, JNK phosphorylation inhibition TR3 and DNA response element binding, inhibition of transcription activation ability of TR3. HEK293T cells, TR3 to promote cell DNA synthesis, and the JNK phosphorylation undermine TR3 mitogen activity. In summary, our study not only the first time to determine the exact sites of JNK phosphorylation of TR3, and close the phosphorylation and ubiquitination, found that the regulation of TR3 is part of the signaling pathways JNK through phosphorylation and pan-biotinylated. These studies may clarify the JNK and TR3 mechanism in the development of certain tumors, for the screening of a specific medication TR3 dependent tumors provide a theoretical basis.
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