Format

Send to

Choose Destination
Mol Cell Biol. 2017 Aug 11;37(17). pii: e00049-17. doi: 10.1128/MCB.00049-17. Print 2017 Sep 1.

Multitiered and Cooperative Surveillance of Mitochondrial Phosphatidylserine Decarboxylase 1.

Author information

1
Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
2
Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA sclaypo1@jhmi.edu.

Abstract

Phosphatidylserine decarboxylase 1 (Psd1p), an ancient enzyme that converts phosphatidylserine to phosphatidylethanolamine in the inner mitochondrial membrane, must undergo an autocatalytic self-processing event to gain activity. Autocatalysis severs the protein into a large membrane-anchored β subunit that noncovalently associates with the small α subunit on the intermembrane space side of the inner membrane. Here, we determined that a temperature sensitive (ts) PSD1 allele is autocatalytically impaired and that its fidelity is closely monitored throughout its life cycle by multiple mitochondrial quality control proteases. Interestingly, the proteases involved in resolving misfolded Psd1ts vary depending on its autocatalytic status. Specifically, the degradation of a Psd1ts precursor unable to undergo autocatalysis requires the unprecedented cooperative and sequential actions of two inner membrane proteases, Oma1p and Yme1p. In contrast, upon heat exposure postautocatalysis, Psd1ts β subunits accumulate in protein aggregates that are resolved by Yme1p acting alone, while the released α subunit is degraded in parallel by an unidentified protease. Importantly, the stability of endogenous Psd1p is also influenced by Yme1p. We conclude that Psd1p, the key enzyme required for the mitochondrial pathway of phosphatidylethanolamine production, is closely monitored at several levels and by multiple mitochondrial quality control mechanisms present in the intermembrane space.

KEYWORDS:

membrane biogenesis; membranes; phosphatidylethanolamine; phospholipids; quality control proteases

PMID:
28606933
PMCID:
PMC5559681
DOI:
10.1128/MCB.00049-17
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center