The ECS(SPSB) E3 ubiquitin ligase is the master regulator of the lifetime of inducible nitric-oxide synthase

Kazuma Matsumoto, Tadashi Nishiya, Satoshi Maekawa, Takahiro Horinouchi, Kouetsu Ogasawara, Takashi Uehara, Soichi Miwa

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)


The ubiquitin-proteasome pathway is an important regulatory system for the lifetime of inducible nitric-oxide synthase (iNOS), a high-output isoform compared to neuronal NOS (nNOS) and endothelial NOS (eNOS), to prevent overproduction of NO that could trigger detrimental effects such as cytotoxicity. Two E3 ubiquitin ligases, Elongin B/C-Cullin-5-SPRY domain- and SOCS box-containing protein [ECS(SPSB)] and the C-terminus of Hsp70-interacting protein (CHIP), recently have been reported to target iNOS for proteasomal degradation. However, the significance of each E3 ubiquitin ligase for the proteasomal degradation of iNOS remains to be determined. Here, we show that ECS(SPSB) specifically interacted with iNOS, but not nNOS and eNOS, and induced the subcellular redistribution of iNOS from dense regions to diffused expression as well as the ubiquitination and proteasomal degradation of iNOS, whereas CHIP neither interacted with iNOS nor had any effects on the subcellular localization, ubiquitination, and proteasomal degradation of iNOS. These results differ from previous reports. Furthermore, the lifetime of the iNOS(N27A) mutant, a form of iNOS that does not bind to ECS(SPSB), was substantially extended in macrophages. These results demonstrate that ECS(SPSB), but not CHIP, is the master regulator of the iNOS lifetime.

Original languageEnglish
Pages (from-to)46-51
Number of pages6
JournalBiochemical and Biophysical Research Communications
Issue number1
Publication statusPublished - 2011 May 27


  • CHIP
  • INOS
  • Proteasomal degradation
  • Ubiquitination


Dive into the research topics of 'The ECS(SPSB) E3 ubiquitin ligase is the master regulator of the lifetime of inducible nitric-oxide synthase'. Together they form a unique fingerprint.

Cite this