Vesicular Traficking III (Lecture 16) Flashcards
The ______-Golgi network sorts proteins into vesicles targeted for different destinations
trans
True or False: Regulated secretory proteins are concentrated and stored until secretion is signaled; constitutively secreted proteins are continuously delivered to the plasma membrane
True
What are the 5 destinations from the trans-Golgi network.
1. COPI vesicle
Retrograde
2. AP3 complex vesicles
may not have clathrin
3. Clathrin-coated vesicles
4. Constitutive secretory vesicles
5. Regulated secretory vesiclesWhat is the outer form structure of clathrin coats?
Triskelion
The inner layer of clathrin coated proteins are composed of _______.
Adapter protein complexes
True or False: Each adapter protein complex determines which cargo proteins are in a vesicle by binding to cytosolic domains of membrane protein.
True
Other then the AP complex, what is another type of adapter protein that is a single large polypeptide and also binds to clathrin and cargo elements.
GGA
______ is known in anterograde or early stages of secretion where as ______ is known in later stages of secretion.
COPII, COPI and Clathrin
For COPI what is the mode of transport, luminal sorting signal, cytoplasmic sorting signal and GTPase for coat assembly/disassembly?
Retrograde transport
KDEL
KKXX and di-arginine
ARF protein
For AP3 complex vesicles what is the mode of transport to, coat protein and GTPase for coat assembly/disassembly?
directly to lysosome
does have clathrin binding site but does not have to use it
ARF protein
______ vesicles that bud from trans-Golgi network en route to the late endosome (eventually to lysosome)
AP1
What is the sorting signal for AP1 vesicles?
Recognize YXXΦsorting signal
Y = Tyr, X = any amino acid, Φ = a bulky, hydrophobic amino acid
______ vesicles that bud from plasma membrane during endocytosis
AP2
True or False: AP2 vesicles also recognize YXXΦsorting signal.
True
______ are also vesicles that bud from trans-Golgi network en route to the late endosome.
GGA
What is the sorting signal for GGA vesicles.
Recognize Asp-X-Leu-Leu and Asp-Phe-Gly-XΦsequences
What are the three types of clathrin coated vesicles.
AP1, AP2, GGA
______ pinches off Clathrin-coated vesicles.
Dynamin
True or False: Dynamin is dependent on ATP.
False, dependent on GTP
True or False: Dynamin polymerizes around the neck of the bud and then hydrolyzes GTP and the conformational change in dynamin stretches the neck until vesicle is pinched off
True
Cytosolic ______ hydrolyzes ATP to depolymerize clathrin into triskelions of clathrin-coated vesicles.
Hsp70
______ vesicles transport constitutively secreted proteins and plasma membrane proteins to the plasma membrane such as ECM proteins, blood proteins, immunoglobulins.
Constitutive secretory
______ vesicles store and process secreted proteins until signaled to fuse with the plasma membrane to secrete the proteins such as digestive enzymes and peptide hormones.
Regulated secretory
True or False: Regulated and Constitutive secretory vesicles have coat proteins that are still unknown.
True
In polarized epithelial cells, the ______ domain is abuts adjacent cells and the underlyingbasal lamina and the ______ domain is exposed to the exterior of the body or to an internal open space (e.g., intestinal lumen, duct) .
Basolateral, Apical
What prevents movement between the apical and basolateral membranes?
Tight junctions
How are apical and basolateral bound membrane proteins sorted?
sorted into their own transport vesicles with unique v-SNAREs and Rab proteins targeting either the apical or basolateral region
Influenza viruses bud from only the ______ membrane and VSV viruses bud from only the ______ membrane.
Apical, basolateral
What are the two types of motifs associated with apical and basolateral bound membrane proteins?
Tyrosine-based, di-leucine-based
Help membrane proteins associate with clathrin adapter proteins
True or False: Proteins targeted to the apical membrane of epithelial cells often have a glycosylphosphatidylionositol (GPI) membrane anchor.
True
What happens endocytosis takes in both basolateral and apical proteins?
Basolateral proteins sorted back to basolateral membrane
Apical proteins move in vesicles across the cell and fuse with apical membrane (Transcytosis)
______ is used to visualize protein size and abundance.
SDS-PAGE
What type of stain is reversible?
Ponceau Red
What type of stain is irreversible and insensitive?
Coomassie Blue
What type of stain is complex and sensitive?
Silver Staining
