PIAS1与SGT相互作用及功能研究

Small glutamine-rich tetratricopeptide repeat-containing protein acts as a co-chaperone, interacting with several essential chaperones, such as Hsp70, Hsp90. Our previous study showed the pro-apoptosis activity of SGT. However, the biological mechanism remains unclear. To further investigate its functions, we used the yeast two-hybrid system to screen a human fetal liver cDNA library and identified PIAS1 (protein inhibitor of activated STAT 1) as an interacting partner of SGT. The association of SGT with PIAS1 was further confirmed by GST-pull down in vitro. According to the different subcellular location of this two molecule and the fact that SGT translocates into nucleus after Geldanamycin (GA) or apoptosis inducer treatment, we revealed SGT interacted with PIAS1 in vivo after it translocated into the nucleus. Further study showed that inhibition of PIAS1 expression by siRNA infected the pro-apoptosis activity of SGT. Finally we concluded that SGT transloacted into the nucleus and induced apoptosis, partially dependent on PIAS1.