2.9 Intracellular Vesicular Trafficking 2 Flashcards
What happens in the R ER?
Ribosomes feed proteins through the Sec61 translocator
What happens in the R ER lumen?
Proteins are folded and gain sugar
Why is the S ER smooth?
Lacks ribosome association
What happens in the S ER?
Where vesicles bud from when cargo needs to go to the golgi
What happens in the S ER lumen?
Lipids gain sugar
What happens to folded and misfolded proteins that want to leave the ER?
Misfolded proteins go to the cytosol for degradation. Folded proteins go to the golgi for sorting.
Misfolded proteins go to the cytosol to be degraded via what?
Translocator
Folded proteins go to the Golgi for sorting via what?
Vesicles.
What proteins would return to the ER? For what Reason?
Rabs, SNAREs and cargo receptors must all go back for recycling.
What is the sorting seq for Rabs,SNAREs and cargo receptors?
KK??
What is the sorting seq for ER lumen resident proteins?
KDEL
What is homotypic fusion?
Many vesicles uncoat and duze with other vesicles. Forming these clusters.
Going from the ER to the Golgi, what part of the golgi is reached first?
Cis then the trans.
What part of the golgi goes to a lysosome?
Trans
What is autophagy?
Digestion of organelles by the lysosome
What are the 3 types of Endocytosis?
Receptor mediated, Phagocytosis, and pinocytosis
Pertaining to receptor mediated endocytosis, what coat does it use? Budding?
Clathrin, and Actin.
Pertaining to receptor mediated endocytosis, what is the cargo selection and cargo?
Receptor and cargo is specific to receptor
Pertaining to receptor mediated endocytosis, what is a good example?
Cholesterol uptake
Pertaining to phagocytosis, what is the coat and budding?
No coat. Budding is pseudopod
Pertaining to phagocytosis, what is the cargo selection and cargo?
Antibody and the cargo is whole cell/large molecules
Pertaining to phagocytosis, what is a good example?
Antigen presentation
Pertaining to pinocytosis, what are the 3 coats used with their select buddings?
- Clathrin:amphi+Actin. 2. Claveolin: lipid composition. 3. No coat: actin.
Pertaining to pinocytosis, what is the cargo selection and cargo?
Not selective and usually bulk fluid and small molecules.
Pertaining to pinocytosis, what are the kinetics for the 3 coats?
Clathrin: fast. Claveolin:Slow. No coat: induced.
Once inside the cell what happens to vesicles?
Vesicle will fuse into an endosome, they mature to get to a lysosome. (Not dealing with coats.)
What is the Early endosome? What does it contain?
Also called sorting endosome. Has Rab5.
What is the EE mediated by?
ESCRT
What are some other functions of ESCRT?
Part of autophagy pathway, help remove protein coats, helps with budding viruses, exosome formation, and bridging between cells
What does the recycling endosome (RE) contain?
Rab11
What does the late endosome (LE) contain?
Rab 7
What are the 3 possible fates of vesicles leave the trans golgi?
- Lysosome. 2/3 basically exocytosis.
What coat do all vesicles that leave the golgi get?
Clathrin coat
What happens if the lysosomes arnt working well?
Inability to break down whats inside the lysosome. Resulting in release (exocytosis) of these micro vesicles (little exosomes).
What are some clinical implications if the lysosomes dont work well? What are some example of these diseases?
Neurodegenerative diseases. Alzheimers.
