Vesicle transport Flashcards
What does the endomembrane system do ?
Divides the cell into different mem bound compartments
Regulates translation, modification and trafficking go P
Turn on/off signal transduction
What structures are involved in the Endomembrane system ?
Nuclear envelope, ER, Golgi, secretory vesicles, lysosomes, autophagosomes, PM
What keeps the integrity of individual organelles ?
Constant bidirectional flow of membrane and proteins
Why do vesicles have a protein coat ?
Add shape ( curve and bud)
Concentrate the protein
Selectivity of cargo
Determines destination
Where do COPI coated vesicles move ?
From Golgi to ER
Where do COPII coated vesicles move ?
ER to Golgi
What three ways do proteins associate with the lipid membrane ?
- Anchored within cytosolic face by amphipathic a helix
- Covalent attachment of lipid group
- Non-covalent interactions with other membrane bound P
What do Clathrin coated vesicles do?
Mediate mem recycling
Transport from plasma mem between endoscopes and Golgi
What is the structure of clathrin coated vesicles ?
3 heavy chains and 3 light chains - assemble triskelions at TGN
Clathrins form outer p lattice
What are the three types of endocytosis ?
- Receptor mediated
- phagocytosis
- Pinocytosis
What are the 3 types of receptor mediated endocytosis ?
Clathrin dependent
Caveolin dependent
Clathrin- and caveolin- independent
What interactions is AP2 involved in ?
Interacts with phospholipids
causing conformational change so it can bind to cargo receptors triggering membrane curvature
What is required for clathrin recruitment, coat assembly and budding?
AP2
What is the structure of AP2?
(Adaptor protein complex)
Hetero tetramic, multi subunit
a, b2, omega 2, u2 chains
Where do Cathrin coated vesicles originated from ?
Plama membranę (endocytosis)
