A Mammalian Autophagosome Maturation Mechanism Mediated by TECPR1 and the Atg12-Atg5 Conjugate

Dandan Chen, Weiliang Fan, Yiting Lu, Xiaojun Ding, She Chen, Qing Zhong

Research output: Contribution to journalArticle

99 Scopus citations

Abstract

Autophagy is a major catabolic pathway in eukaryotes associated with a broad spectrum of human diseases. In autophagy, autophagosomes carrying cellular cargoes fuse with lysosomes for degradation. However, the molecular mechanism underlying autophagosome maturation is largely unknown. Here we report that TECPR1 binds to the Atg12-Atg5 conjugate and phosphatidylinositol 3-phosphate (PtdIns[3]P) to promote autophagosome-lysosome fusion. TECPR1 and Atg16 form mutually exclusive complexes with the Atg12-Atg5 conjugate, and TECPR1 binds PtdIns(3)P upon association with the Atg12-Atg5 conjugate. Strikingly, TECPR1 localizes to and recruits Atg5 to autolysosome membrane. Consequently, elimination of TECPR1 leads to accumulation of autophagosomes and blocks autophagic degradation of LC3-II and p62. Finally, autophagosome maturation marked by GFP-mRFP-LC3 is defective in TECPR1-deficient cells. Thus, we propose that the concerted interactions among TECPR1, Atg12-Atg5, and PtdIns(3)P provide the fusion specificity between autophagosomes and lysosomes and that the assembly of this complex initiates the autophagosome maturation process.

Original languageEnglish (US)
Pages (from-to)629-641
Number of pages13
JournalMolecular cell
Volume45
Issue number5
DOIs
StatePublished - Mar 9 2012

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ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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