β1,4-半乳糖基转移酶2与纤粘连蛋白结合的分子机制的研究

The enzyme b-1,4-galactosyltransferase （β1,4GT） is the key enzyme involved in the sugar chain synthesis through catalyzing the transfer of galactose from UDP-galactose to terminal N-acetylglucosamine to form Galb1à4GlcNAc structure. More and more studies indicated that β1,4GT was involved in many biology processes other than sugar chain synthesis. In this project we explored the function of β1,4GT in neuron regeneration, development of testicle , growth of astrocytoma cell line and the interaction between p58PITSLRE and β1,4GT1. p58PITSLRE could be co-purified withβ1,4GT1 in protein purification. Our study confirmed the interaction of p58PITSLRE and β1,4GT1 in vitro and found that p58PITSLRE could increase the activity of β1,4GT1 without changing its mRNA expression. p58PITSLRE and β1,4GT1 were all involved in the apoptosis of SMMC7721 cells induced by CHX and other stimulation. Our research indicated that p58PITSLRE played different role in the apoptosis induced by VP16, CHX and serum starvation. Overexpression of p58PITSLRE in 7721 cells could suppress the apoptosis induced by VP16, but promote the apoptosis induced by CHX and serum starvation. b1,4GT1 expression was elevated in the apoptosis of 7721 cells induced by CHX. Furthermore, 7721 cells transfected with b1,4GT1 were inclined to apoptosis induced by CHX. We used yeast two-hybrid system to screen p58PITSLRE associated proteins and found that cyclinD3 could interact with p58PITSLRE specifically in G2/M phase. CyclinD3 could enhance the phosphorylation activity of p58PITSLRE towards Histone H1 and b1,4GT1. The interaction of cyclinD3 and p58PITSLRE could accelerate the translocation of p58PITSLRE into nucleus.

我们实验室利用酵母双杂交系统，发现beta1,4半乳糖基转移酶2能与纤粘连蛋白Fn的C端结希狙芯拷徊窖芯克窍嗷プ饔玫那颉⑾掠畏肿雍驮谙赴谒鸬淖饔茫毖芯縝eta1,4GT2超表达和阻断表达对细胞生物学行为的影响，这将使我们对beta1,4GT2的功能有碌娜鲜叮徊窖芯縝eta1,4GT2的生物学功能奠定理论基础。