第七章 真核细胞内膜系统、蛋白质分选与膜泡运输
DESCRIPTION
第七章 真核细胞内膜系统、蛋白质分选与膜泡运输. 第一节 细胞质基质的涵义与功能. 在真核细胞的细胞质中,除去光镜和电镜下可分辨的细胞器和颗粒以外的细胞质中 胶态基底物质 ,称细胞质基质。. 一、细胞质基质的涵义. 由于细胞质基质的独特结构特征及较大的研究难度,以至于现在对细胞质基质还没有一个统一而确切的概念,目前常用的名称是细胞质基质和胞质溶胶,二者虽有差异但常常等同使用。. 细胞质基质与胞质溶胶. 有些学者认为细胞质基质主要是由微管、微丝和中间纤维等形成的相互联系的结构体系。其中蛋白质和其他分子以凝聚态或暂时的凝聚态存在,与周围溶液的分子处于动态平衡。 - PowerPoint PPT PresentationTRANSCRIPT
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RNA
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N
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NMetSer ThrAlaValCysGlyPro N12 N
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N
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HspATP
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:
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:
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()
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(autoradiography) (pulse-chase experiment)(microsomes)
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?
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Porter1945endoplasmic reticulumER
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rough endoplasmic reticulumrER smooth endoplasmic reticulumsER
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rER
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rER
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rER
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sER
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1.
-
2.
-
3.
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N-
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4. Sec61p
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BiPER
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5. P450 6-
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Golgi bodyGolgi apparatusGolgi complex1898Camillo Golgi
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GB(forming face)(cis face) (mature face)(trans face)
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Regions of the Golgi apparatus
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cis transTPP NADP
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1. (cis Golgi)(cis Golgi network, CGN) cis CGN
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2.
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3.TGN TGN TGNTGN TGN
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: 40%, 60%; : 20%, 50-60%; : 60%, 40%;
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1. GBGB
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2. rERERGBERGBGB N Asn-NH2 O SerThrTyr-OH
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3. rERGB GB N
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4. GB GB
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,50,,,
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(heterogenous),0.250.8m1m,25-50nm
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pH4.6-4.8Cl-
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:50(hydrolytic enzymes)pH4.6
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(primary lysosome)(secondary lysosome)(residual body) (post lysosome)(tertiary lysosome )
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-6--6-
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-6- (mannose 6-phosphate, M6P)M6P
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N--6-N- (N-acetyglucosamine phosphotransferase) N-[)]
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(signal patch) , ,
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6-
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M6P(M6P receptor protein)M6PpH6.57M6P(pH=6)M6PM6P
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(peroxisome)(microbody)
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1. P19873
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2. A
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H2O2 H2O2 H2O2
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3.
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1. 2.3 3.
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4. 5. -6-
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(protein targeting)(protein sorting)
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signal sequence sorting receptor
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15-60N
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15-35N-1N-6-12C-
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12(SRP)SRPA3 SRP(DP)
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75SRP64 SRPDP SRPGTPSRP
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( signal recognition particle, SRP)docking protein, DP( translocon)
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signal recognition particle, SRP617SRNAG: SRP
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SPR
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Docking protein,DPSRPG:, SRP
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Sec61 2nm
Sec61, Sec61 10( translocon)
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Signal hypothesis
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(start-transfer sequence)(stop transfer sequence)
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N- N-N- (internal signal sequence) N- (noncleavable)
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N
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(stop transfer sequence)
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NN
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NN
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NC+-
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coat
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? ? ? ?
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(coated vesicles)(clathrin-coated vesicle)COPII(COPII coated vesicles)COPI(COPI coated vesicles)
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1. COP ERGB
ER
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COPII-
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2. COP I 8ARFSar Lys-Asp-Glu-LeuKDEL SRPCLys-Lys-X-X COP I
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ER
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Cop I Vesicles
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Cop I and II Vesicles
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3. TGN
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Clathrin coated vesicles
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Selective transport by clathrincoated vesicles
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dynamin1.5nmpinch off
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SNAREs soluble NSF attachment protein receptor20SNAREsv-SNAREst-SNAREs v-t-SNAREsSNAREstrans-SNAREs complexes
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SNAREs
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NSF
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RabsRabstargeting GTPaseGTP30RabsRabsRabsGDPGTPSNAREsRabseffector
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Rabs in docking
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(molecular chaperones)
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2Bipheavy-chain binding protein)Bip1
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BiPER
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1.2.