The unfolded protein response of the endoplasmic reticulum supports mitochondrial biogenesis by buffering nonimported proteins.
Mol Biol Cell
; 34(10): ar95, 2023 09 01.
Article
in En
| MEDLINE
| ID: mdl-37379206
ABSTRACT
Almost all mitochondrial proteins are synthesized in the cytosol and subsequently targeted to mitochondria. The accumulation of nonimported precursor proteins occurring upon mitochondrial dysfunction can challenge cellular protein homeostasis. Here we show that blocking protein translocation into mitochondria results in the accumulation of mitochondrial membrane proteins at the endoplasmic reticulum, thereby triggering the unfolded protein response (UPRER). Moreover, we find that mitochondrial membrane proteins are also routed to the ER under physiological conditions. The level of ER-resident mitochondrial precursors is enhanced by import defects as well as metabolic stimuli that increase the expression of mitochondrial proteins. Under such conditions, the UPRER is crucial to maintain protein homeostasis and cellular fitness. We propose the ER serves as a physiological buffer zone for those mitochondrial precursors that cannot be immediately imported into mitochondria while engaging the UPRER to adjust the ER proteostasis capacity to the extent of precursor accumulation.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Organelle Biogenesis
/
Endoplasmic Reticulum Stress
Language:
En
Journal:
Mol Biol Cell
Journal subject:
BIOLOGIA MOLECULAR
Year:
2023
Document type:
Article
Affiliation country:
Alemania