- 學位論文
表現人類核糖體蛋白S20，研究S20與ZAK之間的相關性
Expression of human ribosomal protein S20, and study its interaction with ZAK
摘要
ZAK是一種激酶，結構上含有一個kinase catalytic domain，leucine-zipper (LZ)和一個sterile-alpha motif (SAM)，屬於MAP kinase kinase kinase (MAP3K)。當ZAK過度表現於於哺乳動物細胞中時會藉由下游的MKK7間接活化JNK/SAPK訊息傳遞路徑，進而影響到細胞生長停滯 (cell arrest)。ZAK表現在H9c2心臟肌母細胞 (cardiomyoblast cells)會造成心肌細胞型態改變而造成心肌肥大 (cardiac hypertrophy)，其影響心肌肥大一條訊息傳遞路徑為TGF-β＞ZAK＞MKK7＞ANF。哺乳類動物的核糖體是一巨大結構且複雜的系統，由4個核糖體核糖核酸 (ribosomal RNA)分子 (28S, 5.8S, 5S, 18S)及大約80個核糖體蛋白質 (ribosomal proteins)所組成，重要的功能是蛋白質合成。我們利用GST pull-down assay證明了ZAK與S20之間的鍵結關係，發現ZAK羧端600~700的胺基酸片段對於ZAK與S20鍵結是非常重要。以in vitro kinase assay的方法觀察到ZAK可以提高S20磷酸化的表現，而ZAK dn則會降低S20磷酸化的表現。
並列摘要
ZAK is mitogen-activated protein kinase kinase kinase (MAP3K). The leucine-zipper (LZ) and sterile-α motif (SAM) kinase (ZAK) belongs to the MAP kinase kinase kinase (MAP3K) when upon over expression in mammalian cells the JNK/SAPK pathway, comprising a group of highly related serine/threonine kinase. That ZAK activates JNK/SAPK mediated by downstream target, MKK7. The report presented suggests a schematic pathway of ZAK > MKK7 > JNK > cell arrest. The expression of ZAK in cardiomyoblast cells causes dramatic change in cell morphology and induces cardiac hypertrophy via a novel signaling pathway of TGF-β＞ZAK＞MKK7＞ANF. The mammalian ribosome is a complex system which is comprised of four ribosomal RNA molecules (28S, 5.8S, 5S, 18S) and as many as 80 ribosomal proteins. We used GST pull-down to prove that the relationship between ZAK and S20. We found binding between ZAK and S20 is very important with ZAK C-terminal 600~700. In vitro kinase assay, we have identified the increased S20 phosphorylation by ZAK, but S20 phosphorated to decreased by ZAK dn.