Sorting 1 Flashcards
Name the three topological compartments.
1) Nuclear/Cytosol
2) Organells of secretory and endocytic pathways
3) Mitochondria
Which transport mechanism communicates unidirectionally?
TM or Transmembrane transport
Most topological compartments communicate via ___ and ___.
Budding and fusion
How do proteins communicate?
Sorting Signals which are a stretch of 15-60 A.A found at the N, C terminus or middle of the protein sequence.
What is a signal patch?
When protein sequences of sorting signals form their tertiary structure creating a folded congregation.
What removes the protein signal once it reaches final destination?
Signal Peptidase
Signal sequence of “import into nucleus”
Heavy in Lys-Arg sequence
Signal sequence of “import to mitochondria”
Positively charged and hydrophobic A.A
Signal sequence of “import to ER”
Mostly hydrophobic A.A
Signal sequence of “return to ER”
KDEL
NPCs are _____ made of ____ shaped, almost like a ____
Nuclear Pore Complexes, nucleoporins, octagonal shape, baskets.
NPC signals are facilitated by ___
Fibrils off the NPC
NLS are ____ that direct molecules to the nucleus rich in ____ since they are part of nucleus
Nuclear Localization Signals, Lys-Arg
NPCs allow transport via ____ and ____
Passive Diffusion and Facilitated Transport
NLC allow ____ transport
selective
Describe how signals come into the nucleus from cytoplasm
The Nuclear Localization Signal (NLS) and Nuclear import receptors (NIR) bind to either directly or indirectly on the periphery of the nucleus. They travel through Fibril Nuclear Pore Complexes It brings the signal into the nucleus and the NIR goes back into the cytoplasm
Fibrils are made of
FG (phenylalanine glycine) repeats
Just like nuclear import process, nuclear export is conducted by NES or ____ that bind to ____ to allow transport to cytoplasm
Nuclear export signals, nuclear export receptors
In the Cytosol Ran GAP convert G– into G–
GTP–GDP
In the Nucleus, Ran GEF converts G– into G–
GDP–GTP
