Protein Sorting and Transport

Protein Sorting and Transport

1. Endoplasmic Reticulum

   • Rough ER
   • Transitional ER
   • Smooth ER
   • Protein Secretion
     • Secretory Vesicles
     • Secretory Pathway
   • Targeting Proteins
     • Signal Sequence
     • Microsomes
     • Signal Recognition Particle (SRP)
     • SRP RNA
     • SRP receptor
     • Translocon
     • Signal Peptidase
   • Protein Folding and Processing
     • Protein disulfide isomerase (PDI)
     • GPI Anchors
   • Quality Control
     • ER-associate degradation (ERAD)
       • A process in which misfiled proteins in the ER are identified and retired to the cytosol for degradation by the ubiquitin-proteasom system
     • Unfolded preteen response (UPR)
       • A cellular stress response in which an excess of unfolded proteins in the ER leads to general inhibition of protein synthesis, increased expessionof chaperones, and increased proteasome activity
   • Smooth ER and lipid synthesis
     • flippases
       • A protein that catalyzes the translation of lipids across the ER membrane

2. Golgi Apparatus (Golgi complex)

   • cytoplasmic organelle involved in the processing and sorting of proteins and lipids. In plant cells, it is the site of the synthesis of cell wall polysaccharides
   • Organization
     • cis Golgi network
       • region of Golgi where proteins ENTER from ER
     • Golgi stack
       • The compartments of the golgi apparatus within which most metabolic activities take place
     • trans Golgi network
       • Golgi compartment within which proteins are SORTED and packaged to EXIT Golgi
   • Protein glycosylation
     • mannose-6-phosphate
       • Modified mannose residue that targets proteins to lysososomes
     • signal patches
       • Recognition determinant formed by 3D folding of a pp chain
   • Protein sorting and export
     • apical domain
       • Exposed free surface of a polarized epithelial cell
     • basolateral domain
       • Surface region of a polarized epithelial cell that is in contact with adjacent cells or the extracellular matrix
     • vacuole
       • Large membrane-enclosed sac in the cytoplasm of eukaryotic cells. In plant cells, vacuoles function to store nutrients and waste products, to degrade macromolecules, and to maintain turgor pressure

3. Mechanism of Vesicular Transport

   • Synaptic vesicles
   • Clathrin
     • Clathrin coated vesicles
   • COPI
     • COPI coated vesicles
   • COPII
     • COPII coated vesicles
   • Vesicle Fusion
     • SNAREs
     • Rab proteins
     • Exocysts

4. Lysosomes

   • Lysosomal storage diseases
   • Endocytosis and lysosome formation
     • endocytosis
     • endosomes
   • Phagocytosis and autophagy
     • Phagocytosis
       • The uptake of large particles, such as bacteria, by a cell, sometimes called "cell eating"
       • Phagosomes
         • vacuole containting a particle taken up by phagocytosis
       • Phagolysosomes
         • A lysosome that has fused with a phagosome or autophagosome
     • Autophagy
       • Degradation of cytoplasmic proteins and organelles by their enclosure in cytoplasmic vesicles that fuse with lysosomes
       • Autophagosome
         • vesicle containing internal organelles enclosed by fragments of cytoplasmic membranes that fuses with lysosomes