Protein trafficking between membranes. Flashcards
What is the coat used for?
Budding and scission of vesicles.
What happens to the coat before tethering occurs?
It dissociates from the vesicle.
What member of the endomembrane is responsible for endocytosis?
Lysosomes
What member of the endomembrane is responsible for Excocytosis?
Endoplasmic reticulum and Golgi aparatus
What is the sequence of compartments proteins go through to leave a cell
Golgi
Vesicle
Membrane
What are the two processes for Exocytosis
Constitutive and regulated
What are common neurofiliments?
NF-L, NF-M, NF-H
Where are neurofiliment proteins found?
MTOC in neuronal cells.
What do Neurofilaments do?
Stabilize the organization of the endoplasmic reticulum and golgi complex
What is the regulator mechanism for endocytosis
Enzymes are released only when signalled by appropriate stimuli
Where do vesicles move in retrograde transport
From golgi to ER
How are vesicles exiting the endoplasmic reticulum formed?
COP II
Sorting proteins in cytoplasmic tail.
Soluble proteins eneter bulkflow or bind to signal proteins.
What is the targeting signal used to retain resident Golgi protein
Signal anchor and flank sequence.
What are SNARES used for
Docking
Where do COPI vesicles move proteins in forward transport?
From CGN to TGN (Cis golgi to trans golgi)
Where do COPI vesicles move proteins in reverse transport?
From VTC or Golgi to ER.
What is needed for COPI to do reverse transport?
KDEL sequence.
What are the ordered Steps prior to fusion of a vesicle
Budding Scission Uncoating Tethering Docking Fusion
What type of vesicle transport from Golgi to ER in retrograde transport
COPI
What would a cell lacking functional T-SNAREs look like
Docking wouldn’t happen
What is the complex that unwinds v/t-SNARES
NSF
What is the role of SNARE proteins?
To allow for fusion by docking.
Where does ATP hydrolysis occur in the process of fusion to a target membrane?
In unraveling snares via NSF
What does Hsc70 do in endocytosis
Uncoats
What is Hsc70
ATPase
What structure does clathrin form around vesicles that originate in the plasma membrane
A “cage”
What is the function of adaptin proteins
to link clathrin to ligands
How do adaptor proteins link clathrin to membrane proteins?
Through ligands.
What is the retention signal for resident ER proteins
KDEL
What would happen if a cell failed to place mannose-6-phosphate on a protein?
Soluble lysosomal enzymes wouldn’t get sorted.
List the differences between early endosome and lysosome
Lysosome are more acidic and have degradive enzymes.
What is the order of endosomes
Early endosome to late endosome to lysososme
How are clathrin vesicles used in endocytosis
They bring material across the plasma membrane and deliver it to endosomes.
Where do clathrin bring proteins when coming from the golgi in endocytosis
to late endosomes
Where do clathrin bring proteins when coming from the Plasma membrane in endocytosis
Early endosomes.
Where do clathrin bring protein in exocytosis
From condensing vacuole to Golgi
What is the role of clathin in fusion
They are a transport vesicle. they come off before fussion.
What are coated pits made out of?
COPI COPII and Clathrin
What is the role of RabGTP
Tethering.
What is the exit side of the Golgi Network
Trans (TGN)
What is the entrance side of the Golgi Network
Cis (CGN)
How does KDEL incite retrival?
There is a ligand on the KDEL that attaches to COPI and moves to CGN
What degree is the sturcture of Clathrin
Quatrenary
What is Clathrin triskelion made of?
Three heavy chains, three light chains.
