Cellular and molecular mechanism for secretory autophagy

Autophagy. 2017 Jun 3;13(6):1084-1085. doi: 10.1080/15548627.2017.1307486. Epub 2017 Apr 3.


Macroautophagy/autophagy plays a role in unconventional secretion of leaderless cytosolic proteins. Whether and how secretory autophagy diverges from conventional degradative autophagy is unclear. We have shown that the prototypical secretory autophagy cargo IL1B/IL-1β (interleukin 1 β) is recognized by TRIM16, and that this first to be identified secretory autophagy receptor interacts with the R-SNARE SEC22B to jointly deliver cargo to the MAP1LC3B-II-positive sequestration membranes. Cargo secretion is unaffected by knockdowns of STX17, a SNARE catalyzing autophagosome-lysosome fusion as a prelude to cargo degradation. Instead, SEC22B in combination with plasma membrane syntaxins completes cargo secretion. Thus, secretory autophagy diverges from degradative autophagy by using specialized receptors and a dedicated SNARE machinery to bypass fusion with lysosomes.

Keywords: IL1B; SNAREs; TRIMs; ferritin; galectins; inflammasome; unconventional secretion.

MeSH terms

  • Autophagy*
  • Humans
  • Lysosomes / metabolism
  • Membrane Fusion
  • Models, Biological
  • Phagosomes / metabolism
  • SNARE Proteins / metabolism
  • Secretory Pathway*


  • SNARE Proteins