Vesicle Trafficking and Endocytosis Flashcards
where is the major branch point in the secretory pathway
trans golgi network (TGN)
many vesicles that bud from the TGN and/or endocytic vessicles have a coat of ____?
adapter protein (AP) complexes and clathrin
Dynamin is needed for what?
its a pinch-ase. its pinches off clathrin-coated vesicles. it forms a collar around the neck and hydrolyzes GTP
clathrin and AP2 coated vessicles are involved in?
receptor mediated endocytosis
(asn-pro-x-tyr), (leu-leu), and (tyr-x-x-phi)
sorting signals in cytosolic domain of cell-surface receptors that target them into clathrin/AP2 coated pits
what happens during endocytosis of something like LDL particles?
transport vesicles from cell surface by fusing with late endosomes, that then travel to lysosome
mu subunit
recognizes tyrosine sorting signal
endocytosis recovers __, __, __ from plasma membrane
protins, signaling ligands, integral membrane proteins
what is clathrin made of?
a triskelion. (this is turek’s star trek thing)
How is a soluble enzyme targeted for lysosome?
M6P is modified in cis-golgi. it binds to M6P receptors to direct their transport to a late endosome
Ferrotransferrin/apotransferrin
receptor mediated endocytosis for Fe 3+
how is ferrotransferrin different?
the iron is released from the soluble protein due to low pH. BOTH protein and ligand gets recycled
LDL receptor
has NPXY sorting signal (mu subunit of AP2 binds it)
regulated secreted proteins
they are concentrated in secretory vessicles that sit and wait for a hormonal signal that triggers exocytosis
in general, where is proteolytic maturation?
post-golgi proteolytic cleavages occur in vessicles that carry proteins from TGN to cell surface
