Degradation Flashcards
nascent, immature proteins are physically protected–> do not run the risk of having these degraded
ya
basic mechs of action of proteases
Ser, Thr, or Cys proteases–> covalent catalysis (His crucial); and Asp or metalloproteases–> noncov catalysis
what signals can proteins carry that determine their lifetime?
N-terminal 2nd amino acid (N-degron, N-end rule); post-trans mods; intrinsic degradation signals (degrons)
what is the point of AAA+ ATPase?
likely unfold prot and translocate it through barrel
wat is DBRP
dead box recognizing protein, which binds to cyclin degron and recruits ubiq ligase to cyclin
what is HIF-1?
a master regulator of adaptive changes in gene expressions at low O2 tensions
- -under normal O2 conditions, HIF-1a is hydroxylated at proline–>recognized for polyubiq and degraded
- -under low O2 conditions HIF-1a is no longer hydroxylated–>therefore, H1a accumulates and activates expression of a set of stress genes
ER does not contain any proteolytic machinery
ya
the QC system is a hybrid between chaperones and proteases
ya
mito contain a variety of proteases in every compartment, both soluble and membrane-bound–both processing peptidases and ATP-dependent proteases–but only the ATP-dependent proteases function in quality control by sensing the misfolded state of their substrrates
ya
Types of autophagy
macrophagy. microphagy, and chaperone-mediated autophagy
“self-eating”
importance of Pink1 and Parkin
needed to target damaged mito for autophagy; mutations cause parkinson’s disease
ubiq is reversible
ya
mitochondrial QC
have proteases in every subcompartment–>soluble or integral membrane;
contains processing peptidases and ATP-dependent proteases–> only the latter play a role in QC–> sense misfolded state of a protein
ER QC
no proteolytic machinery–>QC system recognizes misfolded, unassembled, and or inappropriately modified proteins
–>chaperone-mediated targeting to the translocon–>proteins unfolded & retrotranslocated; ubiq & go to proteasome
