胞科学 el Science 蔡国
细胞科学 Cell Science （8.4） 蔡国平
7.4 Synthesis, sorting and translocation of proteins synthesized in biosynthesis pathway and secretory pathway 7.4.1 Two types of proteins Except for few nonneuclear-codeded proteins, all proteins begin being synthesized on ribosomes in the cytosol, and further carry out their synthesis and sorting by followed two ways By one way, the proteins are synthesized and sorted bv biosynthesis or secretory pathway, including: secretory proteins enzymes or proteins resident in the lumens of all EMS as well as integral proteins of the membranes of these organelles and the plasma membrane By another way, all other nuclear-encoded proteins are synthesized and released into the cytosol, as described above These proteins remain in the cytosol unless they contain a specific signal sequence that directs them move to the peripheral pi roteins of the inner surface of the plasma membrane, mitochondrion chloroplasts, microbodies, or nucleus and further sorted and located within the membranes or lumens of these organelles
7.4 Synthesis, sorting and translocation of proteins synthesized in biosynthesis pathway and secretory pathway 7.4.1 Two types of proteins: Except for few nonneuclear-codeded proteins, all proteins begin being synthesized on ribosomes in the cytosol, and further carry out their synthesis and sorting by followed two ways: By one way, the proteins are synthesized and sorted by biosynthesis or secretory pathway, including: secretory proteins, enzymes or proteins resident in the lumens of all EMS as well as integral proteins of the membranes of these organelles and the plasma membrane. By another way, all other nuclear-encoded proteins are synthesized and released into the cytosol, as described above. These proteins remain in the cytosol unless they contain a specific signal sequence that directs them move to the peripheral proteins of the inner surface of the plasma membrane, mitochondrion, chloroplasts, microbodies, or nucleus and further sorted and located within the membranes or lumens of these organelles
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7.4.2 Protens synthesized can move or transport between compartments in different ways 1. There are four fundamentally different ways, by which proteins move through the membranes from one compartment into another and even insert into the membranes Gated transport, by which specific macromolecules, even macromolecule assemblies, move between two topological equivalent spaces in continuity through a pore complex, such as NPC (nuclear pore complex) or the channel complex outer membrane of Mit or ChI., although which also allows free diffusion of smaller molecules Transmembrane transport, the membrane-bound protein translocators by which specific proteins, unfolded usually, are directly translocated in snake-like way across the membrane from the cytosol into a space that is topologically distinct. Such as the transportors or translocators in ER membrane (for initial translocation of novel peptide), the membrane of mit or chl
7.4.2 Protens synthesized can move or transport between compartments in different ways 1. There are four fundamentally different ways, by which proteins move through the membranes from one compartment into another and even insert into the membranes: Gated transport, by which specific macromolecules, even macromolecule assemblies, move between two topologically equivalent spaces in continuity through a pore complex, such as NPC (nuclear pore complex) or the channel complex outer membrane of Mit or Chl., although which also allows free diffusion of smaller molecules. Transmembrane transport, the membrane-bound protein translocators by which specific proteins, unfolded usually, are directly translocated in snake-like way across the membrane from the cytosol into a space that is topologically distinct. Such as the transportors or translocators in ER membrane (for initial translocation of novel peptide), the membrane of Mit or Chl