Proteosome Pathway

Question	Answer
20S Subunit- Structure	4 subunits (alternating 2 alpha, 2 beta) with a and b going opposite ways
20S Subunit- Protease	Non specific protease sequestered in the middle, only accessed via a narrow channel
20S Subunit- Protein Unfolding	Proteins must be unfolded to pass through the channel to the protease, so fully folded proteins are protected from accidents
20S Subunit- Protein Selection	Only ubiquitinated proteins are brought to the proteosome
19s Lid- Role	Acts as adocking site, with ATPases and unfoldases to unfold the target protein
Ubiquitin	A 76 aa polypeptide used to flag amino acids for degredation
Ubiquitination- E1	Ubiquitin activating enzyme
Ubiquitination- E1 Role	Ubi binds to it before transfer to E2
Ubiquitination- E2	Ubiquitin Conjugating Enzyme
Ubiquitination- E2 Role	Transfers E2 to E3
Ubiquitination- E3	Ubiquitin Ligating Enzyme
Ubiquitination- E3 Role	Transers ubi to the lysine residue of the target protein
Ubiquitination- Polyubiquitination	If degredation is the aim, the process repeats, adding multiple Ubis together
Ubiquitination- Recycling	Ubis are removed from broken down proteins and reused
Ubiquitination- Cell Growth	Regulates cell growth & proliferation by degrading uncessary transcription factors
Ubiquitination- Mistakes	Removes misfolded/mistargeted proteins

Resource summary

	Created by gina_evans0312 about 10 years ago