Vesicular Traffic II
Endocytic and secretory pathways red = secretory green = endocytic blue = recycling
Different coats are used for different transport steps in the cell
Assembly and disassembly of clathrin coat
Dynamin pinches clathrin coated vesicles from the membrane
Electron micrograph from Drosophila mutant
Resting Chemical Synapse
Drosophila mutant can not recycle synaptic vesicles
SNARE proteins guide vesicular transport
Active Chemical Synapse
Interaction of SNARE proteins while docking synaptic vesicle at nerve terminal
Model for membrane fusion. Tight SNARE pairing forces water molecules from area between lipid bilayers
Entry of HIV into lymphocytes
Recruitment of cargo molecules into ER transport vesicles
Vesicular tubular clusters move along microtubules to carry proteins from ER to Golgi apparatus
Vesicular tubular clusters
Microtubules
DVD Clip 58
3-dimensional model of the Golgi Apparatus
Golgi apparatus in an algal cell
ER – Golgi transitional zone in an animal cell
Some enzymes are enriched in cis or trans compartments of the Golgi substrates specific for certain enzymes such as acid phosphatase
Functional Compartmentalization of the Golgi Apparatus
Golgi apparatus stained with GFP
Golgi apparatus can be polarly distributed In this fibroblast Golgi is facing the direction in which the cell is crawling
Drawing of goblet cell in the intestinal epithelium Secretes polysaccharide rich mucus into the small intestine Golgi is highly polarized to facilitate release of mucus through exocytosis at the apical domain
N-linked glycosylation because sugar is added to N of asparagine. original precursor oligosaccharide added to most proteins in the ER
Oligosaccharide chains are processed in the Golgi common core complex high-mannose
Vesicular transport model
Cisternal Maturation Model
Lysosome interior is different from cytosol
Detection of acid phosphatase in lysosomes Small spheres may be vesicles delivering the enzyme from the Golgi Apparatus