分子細(xì)胞與組織：蛋白質(zhì)的定向運(yùn)輸和分泌

1、蛋白質(zhì)的定向運(yùn)輸和分泌 Intracellular Protein Sorting, Transport, and Secretion,細(xì)胞與細(xì)胞器,細(xì)胞器怎么生成？,蛋白質(zhì)如何形成功能性結(jié)構(gòu)？,新合成的蛋白如何運(yùn)輸?shù)?其細(xì)胞器或功能性位置？,蛋白質(zhì)運(yùn)輸通路（Protein trafficking pathway）,學(xué)習(xí)目標(biāo)(掌握和熟悉）,蛋白質(zhì)靶向運(yùn)輸?shù)幕驹恚ㄐ盘?hào)學(xué)說） 蛋白質(zhì)到內(nèi)質(zhì)網(wǎng)的運(yùn)輸 蛋白質(zhì)到細(xì)胞核的運(yùn)輸 蛋白質(zhì)分泌途徑和生物學(xué)意義 5. 受體介導(dǎo)胞吞,Gnter Blobel & Signal Hypothesis（信號(hào)學(xué)說）,（1999 Nobel Prize Laureat

2、e）,The polypeptide chain passes through an aqueous pore in the translocator(轉(zhuǎn)運(yùn)子).,Signal peptide, SRP and SRP receptor interact with each other to direct attachment of ribosomes to the cytosolic side of the ER membrane.,Its a transmembrane transport，Proteins are imported into ER before complete synt

3、hesis of the polypeptide chainthat is, import is a co-translational translocation (共翻譯轉(zhuǎn)運(yùn)).,Signal Hypothesis,to,Soluble protein,signal hypothesis,tranmembrane protein,Table 15-3 Essential Cell Biology ( Garland Science 2010),信號(hào)肽指導(dǎo)蛋白質(zhì)運(yùn)輸?shù)讲煌哪康牡?三種運(yùn)輸方式：,核孔門控運(yùn)輸,跨膜運(yùn)輸,小泡運(yùn)輸,Figure 15-8 Essential Cell Biolo

4、gy ( Garland Science 2010),核孔的結(jié)構(gòu),Figure 15-9 Essential Cell Biology ( Garland Science 2010),蛋白質(zhì)運(yùn)輸?shù)胶?核運(yùn)輸受體,核定位信號(hào) （positive charge）,Figure 15-10 Essential Cell Biology ( Garland Science 2010),運(yùn)輸是耗能過程,Mitochondrial uptake signalis an amphipathic helix,Arg, Lys (+ charged),N terminus,20-50 aa residues l

5、ong,hydrophobic residues,Figure 15-11 Essential Cell Biology ( Garland Science 2010),蛋白質(zhì)運(yùn)輸?shù)骄€粒體（跨膜運(yùn)輸）,Signal Sequence Binds to Receptor,Hsp70,COO-,outer membrane,inner membrane,MITOCHONDRIAL MATRIX,CYTOSOL,TOM,TIM,receptor,pore,？,為什么需要結(jié)合到Hsp伴侶蛋白？,Unfolded protein + Hsp,跨膜運(yùn)輸需要 unfolding,防止folding 保護(hù)不被

6、降解,Proteins are unfolded,Receptor Transfers Protein to TOM,+,+,+,+,+,+,+,-,-,-,-,-,-,-,Electrochemical gradient,COO-,3. Hsp70 detaches as polypeptide passes through membranes,4. Transit sequence cleaved,targeting sequence,protease (peptidase),Protein folds in the matrix,5. Mitochondrial Hsp70 binds

7、and releases polypeptide as it enters the matrix,6. Polypeptide folds aided by Hsp60,Hsp60,ATP,Hsp70,Additional targeting sequences need to target other locations,Independent sorting signals are required for every transport step!,Example: ATP Synthase subunit on inner membrane,核糖體有兩種存在方式:,自由型,ER結(jié)合型,

8、Figure 15-12 Essential Cell Biology ( Garland Science 2010),內(nèi)質(zhì)網(wǎng)附著有核糖體:粗面內(nèi)質(zhì)網(wǎng),Co-translational translocation,Post-translational translocation,Figure 15-14 Essential Cell Biology ( Garland Science 2010),共翻譯轉(zhuǎn)運(yùn),Figure 15-15 Essential Cell Biology ( Garland Science 2010),運(yùn)輸?shù)紼R腔內(nèi),Figure 15-16 Essential Cel

9、l Biology ( Garland Science 2010),運(yùn)輸?shù)紼R膜上,Figure 15-17 Essential Cell Biology ( Garland Science 2010),運(yùn)輸?shù)紼R膜上,Figure 15-18 Essential Cell Biology ( Garland Science 2010),小泡運(yùn)輸,Figure 15-19a Essential Cell Biology ( Garland Science 2010),小泡的形成,Figure 15-20 Essential Cell Biology ( Garland Science 2010

10、),有被小泡的形成,Coated Proteins:,rough ER,cis,trans,medial,golgi,COPII,COPI,clathrin,plasma membrane,Table 15-4 Essential Cell Biology ( Garland Science 2010),有被小泡的類型,In most case,the vesicle is actively transported by motor proteins that move along cytoskeletal fibers.,小泡通過微管運(yùn)輸,Motor proteins,For their d

11、iscoveries of machinery regulating vesicle traffic a major transport system in our cells,Figure 15-21 Essential Cell Biology ( Garland Science 2010),小泡的靶向運(yùn)輸：靶細(xì)胞器的選擇機(jī)制,Rab：60個(gè)，引導(dǎo)至靶膜 SNARE：20個(gè)， 融合,Rab的選擇作用,Figure 15-23 Essential Cell Biology ( Garland Science 2010),蛋白質(zhì)中內(nèi)質(zhì)網(wǎng)中的加工過程,Figure 15-24 Essential

12、 Cell Biology ( Garland Science 2010),在內(nèi)質(zhì)網(wǎng)中蛋白質(zhì)需要折疊好后進(jìn)入小泡,伴侶蛋白幫助蛋白質(zhì)在內(nèi)質(zhì)網(wǎng)中折疊,內(nèi)質(zhì)網(wǎng)應(yīng)急 ER stress,細(xì)胞凋亡,從高爾基體到細(xì)胞外的小泡運(yùn)輸,固有分泌,受調(diào)分泌,multiple components of extracellular matrix are released from fibroblast by constitutive secretion,固有分泌途徑,Figure 15-28 Essential Cell Biology ( Garland Science 2010),受調(diào)的胞吐過程,受調(diào)分泌途徑

13、,GLUT2攝入 葡萄糖,胰島素分泌,(Ca+-binding protein),肉毒肝菌毒素,Neurotransmitter Synaptic vesicle synoptotagmin,Figure 15-27 Essential Cell Biology ( Garland Science 2010),受調(diào)分泌的蛋白質(zhì),具有受調(diào)分泌功能的細(xì)胞,激素（Hormone） 粘液 （mucus） 消化酶 （digestive enzymes）,哪些組織細(xì)胞有分泌蛋白質(zhì)的功能？,上皮組織？,結(jié)締組織？,肌肉組織？,神經(jīng)組織？,腸腔,哪些組織細(xì)胞有分泌蛋白質(zhì)的功能？,上皮組織中的腺上皮細(xì)胞,外分泌

14、腺,內(nèi)分泌腺,外分泌腺細(xì)胞：分泌胰酶,胰島-內(nèi)分泌腺細(xì)胞 分泌胰島素等,上皮組織 例1: 胰腺,55,蛋白質(zhì)合成、轉(zhuǎn)運(yùn)至高爾基體,胰腺外分泌細(xì)胞超微結(jié)構(gòu)形態(tài)及分泌泡形態(tài) 細(xì)胞中胰酶合成和分泌的過程,糙面內(nèi)質(zhì)網(wǎng),箭頭： 高爾基體,高爾基體,分泌顆粒的形成,胰腺內(nèi)分泌細(xì)胞分泌胰島素的調(diào)控,正確時(shí)間，受調(diào)分泌,GLUT2攝入葡萄糖,胰島素分泌,胰島素的作用,胰島素作用靶細(xì)胞： 脂肪細(xì)胞和肌細(xì)胞,促進(jìn)靶細(xì)胞攝入大量葡萄糖,例2: 小腸上皮組織中有分泌蛋白質(zhì)功能的細(xì)胞,上皮組織,上皮組織 例2: 粘液分泌細(xì)胞（消化道上皮）,分泌細(xì)胞外基質(zhì),結(jié)締組織,成纖維細(xì)胞,疏松結(jié)締組織（HE),例1:成纖維細(xì)胞,電

15、鏡（成纖維細(xì)胞）,1.RER,2.Golgi,固有分泌的方式釋放,結(jié)締組織,分泌細(xì)胞外基質(zhì),例1:成纖維細(xì)胞,例2: 漿細(xì)胞,結(jié)締組織,病原入侵的組織中富含漿細(xì)胞,電鏡 （細(xì)胞核內(nèi)：車輪狀） 富含RER,（合成分泌抗體）,Mast cell,例3: 肥大細(xì)胞,結(jié)締組織,消化道，呼吸道管壁的結(jié)締組織中,電鏡 大量分泌顆粒,分泌組織胺等，也分泌一些蛋白質(zhì),例1:神經(jīng)元,神經(jīng)組織,（合成結(jié)構(gòu)蛋白和分泌蛋白）,尼氏體,受體介導(dǎo)的胞吞（Endocytosis）,Transcytosis of maternal IgG immunoglobulins across the intestinal epith

16、elial cells of newborn mice,biosynthetic-secretory pathway,Vesicular transport,Endocytic pathway,胞吞小泡的命運(yùn),溶酶體,溶酶體及其消化作用,How are membrane-bound proteins delivered to lysosomes?,Lodish 17-31,Overview of vesicular transport,Three intracellular protein trafficking pathways:,Summary,Co-translational trans

17、location,biosynthetic-secretory pathway,Post-translational translocation,Endocytic pathway,Figure 15-5 Essential Cell Biology ( Garland Science 2010),Proteins are imported into organelles by three mechanisms,Gated transport,Transmembrane transport,Vesicular transport,Targeting signals are the pieces

18、 of information that enable the cellular transport machinery to correctly position a protein inside or outside the cell. This information is contained in the polypeptide chain or in the folded protein. The continuous stretch of amino acid residues in the chain that enables targeting are called signal peptides or targeting peptides. Other signals, known as signal patches, are composed of parts which are separate in the primary sequence. They become functional