Receptors bind the nuclear localization signal; that complex then interacts with fibrils to get through the pore; GTP expended; filters through unstructured proteins in pore signal that are about 15-60 amino acids long that direct proteins to specific organelles (usually depending on the hydrophobicity and placement of charges in signal) (signal often removed once protein reaches destination) set of 8 or more phobic amino acids that marks a polypeptide for transport to the endoplasmic reticulum where synthesis of the polypeptide chain is completed and the signal sequence removed 1

1. Transport to the Nucleus

Receptors bind the nuclear localization signal; that complex then interacts with fibrils to get through the pore; GTP expended; filters through unstructured proteins in pore

2. Sorting Signals

signal that are about 15-60 amino acids long that direct proteins to specific organelles (usually depending on the hydrophobicity and placement of charges in signal) (signal often removed once protein reaches destination)

3. ER Signal Sequence

set of 8 or more phobic amino acids that marks a polypeptide for transport to the endoplasmic reticulum where synthesis of the polypeptide chain is completed and the signal sequence removed

4. How proteins are released into ER

1. SRP (signal recognition particle) binds signal sequence
2. complex binds SRP receptor
3. signal peptide binds to channel and protein goes through the translocation channel
4. signal peptidase cuts of signal sequence

tend to be proteins that need to be inside an organelle, outside the cell, or in ER itself (cytosolic)

5. How proteins are inserted into ER membrane

same as released into ER lumen, but transfer is halted when proteins reaches the stop-transfer sequence

tend to be membrane bound proteins that might go to another membrane of an organelle or the cell membrane (membrane bound)

6. Single-pass Membrane Protein

only one stop sequence, and end terminal cleavage occurs (only anchored by stop sequence)

7. Double-pass Membrane Protein

start sequence is not all the way at end, so N terminus remains outside, internal start sequence is therefore not cleaved, end up anchored by start and stop sequences

8. Vesicles

very small, membrane enclosed units that move proteins from organelle to organelle or membrane to membrane

9. Cargo Receptors

bind the molecule

10. Adaptins

bind the cargo receptors, and will be bound to clathrin coat