8. 1. The dynamic nature of the endomembrane system a dynamic, integrated network in which materials are shuttled back and forth from one part(the membrane of donor organelles) of the cell to another (the membrane of acceptor compartment) by transport vesicles. Repeated cycle of budding and fusion of transport vesicles move materials along pathways and tracks formed by cytoskeleton through the cell
8.1. The dynamic nature of the endomembrane system A dynamic, integrated network in which materials are shuttled back and forth from one part (the membrane of donor organelles) of the cell to another (the membrane of acceptor compartment) by transport vesicles. Repeated cycle of budding and fusion of transport vesicles move materials along pathways and tracks formed by cytoskeleton through the cell
verectsery ndaa po)Endosome Lysosome Regula Receptor Don
Several distinct pathways for transport of materials through the endomembrane system (1) Biosynthetic pathway: along this pathway materials are synthesized in ER or GC, modified and incorporated into the ER, GC, lysosomes and a variety of vacuoles during passage and transport from er to the gC and to various destination organelles(plasma membrane, and organelles of EMS etc. (2)Secretory pathway: materials synthesized in ER or GC are destined to be discharged to extracellular space fro om the cell (secretion)-by two types Constitutive secretion to form both ECM and the plasma membrane itself in a continual batch manner for most cells Regulated secretion: first stored in secretory granules, in the peripheral area and then discharged hormones, digestive enzymes and neurotransmitters etc. only in response to an appropriate stimulus
Several distinct pathways for transport of materials through the endomembrane system: (1) Biosynthetic pathway: along this pathway, materials are synthesized in ER or GC, modified and incorporated into the ER, GC, lysosomes and a variety of vacuoles during passage and transport from ER to the GC, and to various destination organelles (plasma membrane, and organelles of EMS etc.). (2) Secretory pathway:materials synthesized in ER or GC are destined to be discharged to extracellular space from the cell (Secretion)–by two types: Constitutive secretion to form both ECM and the plasma membrane itself in a continual batch manner for most cells. Regulated secretion: first stored in secretory granules, in the peripheral area and then discharged hormones, digestive enzymes and neurotransmitters etc. only in response to an appropriate stimulus
Lipids, carbohydrates and the most proteins synthesized in the cell are all transported through the cell along the above two pathways (3)Endocytic pathway: by this pathway, materials move from the surface of the cell to compartments such as endosomes and lysosomes etc. within the cytoplasm Like to trucks transport, it require defined traffic patterns (pathways and vehicles) and is specifically targeted using specific addresses or sorting signals
* Lipids, carbohydrates and the most proteins synthesized in the cell are all transported through the cell along the above two pathways. (3) Endocytic pathway: by this pathway, materials move from the surface of the cell to compartments, such as endosomes and lysosomes etc. within the cytoplasm. Like to trucks transport, it require defined traffic patterns (pathways and vehicles) and is specifically targeted using specific addresses or sorting signals
Nuclear Golgi comple (5 Secretory vesicles envelope GN TGN aNterograde transport 5a constitutive Exocytosis secretion Secretory (6)Late Nucleus ② Lysosome ( ○ endosome Plasma membrane ① Rough ER 39的-叫m Figure 12-8 Vesicular Traffic Through the Endomembrane System vesicles bud off to form secretory vesicles or endosomes Vesicles carry lipids and proteins along several routes from the ER through depending on their protein content. Secretory vesicles move to the plasma the Golgi complex to various destinations, including secretory vesicles membrane where they release their contents by exocytosis, either 52 endosomes, and lysosomes. O Proteins are synthesized by ribosomes constitutively or e9 in response to an appropriate signal. O Proteins and attached to the cytosolic surface of the rough ER. Initial glycosylation steps other material are taken into the cell by endocytosis, forming endocytic occur within the ER lumen. @2 Transition vesicles carry newly synthesized vesicles that fuse with (a endosomes. @ existing lysosomes, or (e the and glycosylated proteins to the CGN. (3 Proteins move through the cisternae of the Golgi stack via shuttle vesicles. Glycoproteins are further TGN, depending on the nature of the enclosed material. (8)Cellular components not destined for digestion following endocytosis are recycled processed in various compartments. Retrograde traffic retums to the plasma membrane. 9 Material for digestion travels to a late compartment-specific proteins to earlier compartments. At the TGN endosome, which becomes a lysosome