Golgi-resident small GTPase Rab33B interacts with Atg16L and modulates autophagosome formation

Takashi Itoh, Naonobu Fujita, Eiko Kanno, Akitsugu Yamamoto, Tamotsu Yoshimori, Mitsunori Fukuda

Research output: Contribution to journalArticle

179 Citations (Scopus)

Abstract

Macroautophagy is a mechanism of degradation of cytoplasmic components in all eukaryotic cells. In macroautophagy, cytoplasmic components are wrapped by double-membrane structures called autophagosomes, whose formation involves unique membrane dynamics, i.e., de novo formation of a double-membrane sac called the isolation membrane and its elongation. However, the precise regulatory mechanism of isolation membrane formation and elongation remains unknown. In this study, we showed that Golgi-resident small GTPase Rab33B (and Rab33A) specifically interacts with Atg16L, an essential factor in isolation membrane formation, in a guanosine triphosphate-dependent manner. Expression of a GTPase-deficient mutant Rab33B (Rab33B-Q92L) induced the lipidation of LC3, which is an essential process in autophagosome formation, even under nutrient-rich conditions, and attenuated macroautophagy, as judged by the degradation of p62/sequestosome 1. In addition, overexpression of the Rab33B binding domain of Atg16L suppressed autophagosome formation. Our findings suggest that Rab33 modulates autophagosome formation through interaction with Atg16L.

Original languageEnglish
Pages (from-to)2916-2925
Number of pages10
JournalMolecular biology of the cell
Volume19
Issue number7
DOIs
Publication statusPublished - 2008 Jul 1

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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