《基质与内膜》.ppt

Chapter 6 Cytoplasmic matrix, Endomembrane system, Protein Sorting and membrane trafficking Cytoplasmic matrix and its functions Functions of cytoplasmic matrix: B. Endomembrane System Gated transport: Vesicular transport 作 业 膜泡表面标志与膜泡运输 过氧化物酶体中蛋白质的来源及输入机制 COPI-coated vasicles transporting Escaped ER resident Proteins Back to the ER. The assembly of a COPI-coat is mediated by ADP-ribosylation factor(ARF), GTP binding protein, which is required for vesicle transfer between cisternae. COPI coated vesicles may select specific cargo. ? ER is an open prison. ? Soluble ER protein bear Retrieving signal—KDEL(Lys-Asp-Glu-Leu)in mammal and HDEL in yeast, whereas ER membrane proteins bear the signal KKXX .?The KDEL receptor present in vesicular tubular clusters and the Golgi apparatus.. (3) COPI-coated vesicle were first identified by treatment of GTP analogues --- COPI-coated vesicle accumulated within the cell and could be isolated by centrifugation. A model for the retrieval of ER resident proteins. The KDEL receptor captures the soluble ER resident proteins and carries them in COPI-coated transport vesicles back to the ER. Neutral pH: dissociate from the KDEL; low pH: binding the KDEL Clathrin-coated vesicle: Transporting Cargo from the TGN to endosomes, Lysosomes, and plant vacuoles and also move materials from the PM to cytoplasmic compartments along the endocytic pathway. The TGN of Golgi is the Sourse of Clathrin-coated vesicle. (2) Clathrin-coats contain: protein clathrin-----which forms a structural scaffold, adaptors---- multisubunit,which forms an inner shell. Biogenesis of the Golgi apparatus in living parasites. a–h, Transgenic parasites stably expressing IMC1–CFP (blue) were transfected with plasmid DNA encoding GRASP–YFP (green). After 20 h of infection in HFFs, four parasites were imaged by time-lapse video fluorescence microscopy. Images were taken every 10 min for 7 h at 37 °C. Representative images at the indicated times a