本計畫對lymphoblastoid cells 其甲基接受蛋白質之分析已建立系統﹐整理其結果之論文Protein N-arginine methylation in subcellular fractions of lymphoblastoid cells已整理投稿Journal Biochemistry中。我們延續此部分結果，進一步已針對某些特殊甲基接受蛋白如一32 Kd polypeptide 作進一步分析鑑定。同時正在發展2-D 蛋白電泳系統及蛋白純化系統以便有系統的從事此工作。而Recombinant fibrillarin 分析也已完成某些protease 之切割正對digestion產物進行分析中。本期計畫進行初期遭逢九二一地震，實驗室受創不淺，細胞培養等工作亦停頓較久以致進度較為落後，現已恢復常軌，逐漸趕上。而2-D 蛋白電泳系統及蛋白純化系統之建立﹐亦可為後續實驗﹐奠立良好基礎。 Based on our previous investigations of protein arginine methylation in lymphoblastoid cells, we pursued the protein arginine methylation in two directions: (1) To further investigate the methylaccepting substrates: How the methylaccepting polypeptides are methylated What are the differences between the methylated and unmodified RGG proteins We will use a nucleolar RGG protein fibrillarin as a model substrate to study arginine methylation. We will also continue the analyses of themethylaccepting polypeptides in lymphoblastoid cells. (2) To further investigate the regulation of the protein arginine methyltransferase activity: We will further identify the activity in different cellular compartments in different cell systems to examine the results of previous investigations of the type I methyltransferases. We will also manipulate the culture conditions to monitor if the methyltransferase activity can be regulated. We also would like to know what are the other polypeptides in the high molecular weight arginine methyltransferase complex and if they are involved in the regulation of the activity of the enzyme. We hope that through our analysis of the methylaccepting substrates and the methyltransferases, by the end of the project, we will have a better picture of why these proteins are methylated and how the modification is regulated in cells.
