Peptide directoryWhole body

PIGBOS

A micropeptide on the outer mitochondrial membrane that talks to the stressed ER.

Where it comes from

Made in
Every cell, as far as is known
Sent out by
Not secreted
Acts on
  • Endoplasmic reticulum at mitochondria-ER contacts

What it does

  • Dampens the unfolded protein response of the ER from the other side of the contact, the first job found for a mitochondrial protein in that pathway 1
  • Cells without it mount a stronger unfolded protein response and die more readily under ER stress 1
  • Found in 2019 by labelling proteins on the mitochondrial surface, not by reading the gene, which had been passed over 1

In medicine

  • None. PIGBOS is not secreted and does not circulate, so there is nothing to measure in blood and nothing to give
  • No human disease has been tied to it, and no variant of PIGBOS1 has been reported as causing one

Beyond the body’s own use

  • Nothing is in trials, and an injected peptide is not the route: PIGBOS works anchored in a membrane inside the cell, one end reaching across to the endoplasmic reticulum 1
  • The question is whether the contact between mitochondria and the ER can be tuned deliberately, since losing PIGBOS leaves cells less able to survive ER stress 1
  • It belongs to a class more than to a story: surveys have found hundreds of micropeptides from short open reading frames that were never annotated as genes, and PIGBOS is one of the few with a job pinned on it 2

Sources

  1. Chu et al., Regulation of the ER stress response by a mitochondrial microprotein, Nature Communications 2019
  2. Slavoff et al., Peptidomic discovery of short open reading frame-encoded peptides in human cells, Nature Chemical Biology 2013

This card describes what a medicine is for and what the evidence says; it recommends nothing. Talk to your clinician about anything you read here.