细胞生物学蛋白分选.ppt

本文档共49页；当前第1页；编辑于星期二\5点32分 本文档共49页；当前第2页；编辑于星期二\5点32分 Golgi本文档共49页；当前第3页；编辑于星期二\5点32分 ？本文档共49页；当前第4页；编辑于星期二\5点32分 1972年，C.Milstein发现在骨髓瘤细胞中提取的免疫球蛋白分子的N端要比分泌到细胞外的免疫球蛋白分子N端多一段氨基酸序列。本文档共49页；当前第5页；编辑于星期二\5点32分 一、The Signal Hypothesissite of synthesis determined by information contained in N-terminus of protein (first part to emerge from ribosome)mRNASignal peptideN信号假说本文档共49页；当前第6页；编辑于星期二\5点32分 The Nobel Prize in Physiology or Medicine 1999“Dr. Guenter Blobel at New Yorks Rockefeller University won the Nobel Prize in medicine Monday (October, 1999) for discovering how proteins find their rightful places in cells ………..”Günter Blobel, born in 1936, works at the Laboratory of Cell Biology, The Rockefeller University, New York 本文档共49页；当前第7页；编辑于星期二\5点32分 Signal hypothesisHow do newly synthesized proteins find their correct destinations within a cell?and how are they able to pass across the tightly sealed intracellular membranes? 本文档共49页；当前第8页；编辑于星期二\5点32分 ER protein has N-terminal signal sequence, cytosolic protein does not.Signal peptide required for import into ER本文档共49页；当前第9页；编辑于星期二\5点32分 Role of signal sequence in protein sortingER protein has N-terminal signal sequence, cytosolic protein does not.What would happen if ER signal sequence put on cytosolic protein?本文档共49页；当前第10页；编辑于星期二\5点32分 Role of signal sequence in protein sorting Putting signal sequence onto normally cytosolic protein results in its import into ER, i.e. signal sequence is sufficient and necessary for ER translocation.本文档共49页；当前第11页；编辑于星期二\5点32分 Signal peptideConsists of short stretch of amino acids (15-25 amino acids)No sequence homology - but is structural homology, notably hydrophobic amino acids本文档共49页；当前第12页；编辑于星期二\5点32分 本文档共49页；当前第13页；编辑于星期二\5点32分 本文档共49页；当前第14页；编辑于星期二\5点32分 Signal sequence directs ribosomes to bind to ER membrane before protein fully synthesised本文档共49页；当前第15页；编辑于星期二\5点32分 Who Introduct Ribosome to the Endoplasmic Reticulum？本文档共49页；当前第16页；编辑于星期二\5点32分 Co-Translational Transport