AMSH, an ESCRT-III associated enzyme, deubiquitinates cargo on MVB/late endosomes

Masanao Kyuuma, Kazu Kikuchi, Katsuhiko Kojima, Yuriko Sugawara, Mariko Sato, Nariyasu Mano, Junichi Goto, Toshikazu Takeshita, Akitsugu Yamamoto, Kazuo Sugamura, Nobuyuki Tanaka

Research output: Contribution to journalArticlepeer-review

41 Citations (Scopus)

Abstract

The appropriate sorting of vesicular cargo, including cell-surface proteins, is critical for many cellular functions. Ubiquitinated cargo is targeted to endosomes and digested by lysosomal enzymes. We previously identified AMSH, a deubiquitination enzyme (DUB), to be involved in vesicular transport. Here, we purified an AMSH-binding protein, CHMP3, which is an ESCRT-III subunit. ESCRT-III functions on maturing endosomes, indicating AMSH might also play a role in MVB/late endosomes. Expression of an AMSH mutant lacking CHMP3-binding ability resulted in aberrant endosomes with accumulations of ubiquitinated cargo. Nevertheless, CHMP3-binding capability was not essential for AMSH's in vitro DUB activity or its endosomal localization, suggesting that, in vivo, the deubiquitination of endosomal cargo is CHMP3-dependent. Ubiquitinated cargo also accumulated on endosomes when catalytically inactive AMSH was expressed or AMSH was depleted. These results suggest that both the DUB activity of AMSH and its CHMP3-binding ability are required to clear ubiquitinated cargo from endosomes.

Original languageEnglish
Pages (from-to)159-162
Number of pages4
JournalCell structure and function
Volume31
Issue number2
DOIs
Publication statusPublished - 2006

Keywords

  • Deubiquitination
  • ESCRT-III
  • Endosome
  • MVB
  • Ubiquitin

ASJC Scopus subject areas

  • Physiology
  • Molecular Biology
  • Cell Biology

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