Week 10 A - Proteosome and Autophagy

Flashcards on Protein Homeostasis, the Proteasome, and Autophagy.

Protein Homeostasis

Maintained by the balance between protein production and protein turnover; each protein has its own half-life (T1/2) which can vary; can be modified by post-translational modification.

Protein Turnover

The process by which proteins are degraded and replaced; part of maintaining protein homeostasis.

Hsp60

Molecular chaperones that monitor protein quality and assist in proper folding.

Proteasome

A protein complex found in the cytosol and nucleus responsible for degrading unneeded or damaged proteins via proteolysis.

26S Proteasome

A form of the proteasome with broad substrate specificity that degrades ubiquitinated proteins.

Ubiquitylation

A post-translational modification where ubiquitin is attached to a protein, often targeting it for degradation.

Ubiquitin (Ub)

A 76 amino acid protein that is attached to other proteins via ubiquitylation.

E1 enzyme

Ubiquitin activating enzyme involved in ubiquitylation of proteins.

E2 enzyme

Ubiquitin conjugating enzyme involved in ubiquitylation of proteins.

E3 enzyme

Ubiquitin ligase involved in ubiquitylation of proteins.

Autophagy

A cellular process involving the degradation and recycling of cellular components, including protein aggregates and worn-out organelles.

Macroautophagy

A type of autophagy involving the formation of autophagosomes to engulf cargo.

Microautophagy

A type of autophagy where lysosomes directly engulf cytoplasmic components.

Chaperone-mediated autophagy (CMA)

A type of autophagy where unfolded proteins are directly translocated into lysosomes with the help of chaperone proteins.

Mitophagy

Selective autophagy of mitochondria

mTORC1

A kinase that inhibits autophagy when nutrients are rich; inhibited by nutrient starvation.

LC3

Microtubule-associated protein 1A/1B-light chain 3, a protein involved in autophagosome formation; LC3-II is lipidated form, associated with autophagosomes.

Autophagosome

A vesicle formed during autophagy that engulfs cellular components for degradation.

Autolysosome

The structure formed when an autophagosome fuses with a lysosome, leading to degradation of the autophagosome contents.