Interaction Between Chaperone And Interleukin-2 Proliferation Signaling--Functional Study Of Signal Molecule Chaperone Hsp90

Interleukin-2 (IL-2) is one of the key cytokines in the immune system whose major function is to stimulate the proliferation of multiple immunocytes. In this thesis, it was demonstrated that the cellular folding system is involved in its proliferation signaling, and the "signal molecule chaperone" Hsp90 has the predominant function. As an indispensable member of "signalsome", Hsp90 palys important roles in the acitvation and regulation of several signal molecules.The rapidly activated transcription factor Stat5 is one of the important effectors in the proliferation signal of IL-2. It was discovered that Stat5 and Hsp90 could form specific complex, which is vital to its activation. Moreover, the region responsible for "Stat5-Hsp90" interaction has been verified to be located in the coiled-coil region of Stat5.Src tyrosine kinase p56Lck is the indispensable upstream kinase in the IL-2 proliferation signal. In this thesis, it was proved that the cellular protein level of p56Lck is maintained by interacting with Hsp90, and the influence of Geldanamycin (GA) on its downstream signaling was also examined. In addition, using the modification domain of p56Lck as the "bait", yeast "two-hybrid" screen in a cDNA library of peripheral blood leukocytes was performed in order to search for the new interacting molecules.Telomerase activity is the key determinant to the cell proliferation and senescence. In this work, it was demonstrated that Hsp90 ensured the IL-2-induced acitvity of telomerase in vitro and in vivo. The second part of the thesis is focused on the mechanism of IL-2-induced TNF-β gene transcription initialization. It was discovered that there was another important -130EBS element in its promoter region, in addition to the -200GASL1 element regulated by the "Jak-Stat" pathway. Moreover, p38 MAP kinase was found to be responsible for the activation of -130EBS element, indicating that MAPK pathway takes a role in transcription stimulation of TNF-β gene by coordinating with Jak-Stat pathway. Moreover, yeast one-hybrid screen was performed in search of the factors binding the -130EBS element.