Menin uncouples Elk-1, JunD and c-Jun phosphorylation from MAP kinase activation

Adriana Gallo, Concetta Cuozzo, Ilaria Esposito, Marcello Maggiolini, Daniela Bonofiglio, Adele Vivacqua, Maria Garramone, Carsten Weiss, Dirk Bohmann, Anna Maria Musti

Research output: Contribution to journalArticlepeer-review

83 Scopus citations

Abstract

Menin, a nuclear protein encoded by the tumor suppressor gene MEN1, interacts with the AP-1 transcription factor JunD and inhibits its transcriptional activity. In addition, overexpression of Menin counteracts Ras-induced tumorigenesis. We show that Menin inhibits ERK-dependent phosphorylation and activation of both JunD and the Ets-domain transcription factor Elk-1. We also show that Menin represses the inducible activity of the c-fos promoter. Furthermore, Menin expression inhibits Jun N-terminal kinase (JNK)-mediated phosphorylation of both JunD and c-Jun. Kinase assays show that Menin overexpression does not interfere with activation of either ERK2 or JNK1, suggesting that Menin acts at a level downstream of MAPK activation. An N-terminal deletion mutant of Menin that cannot inhibit JunD phosphorylation by JNK, can still repress JunD phosphorylation by ERK2, suggesting that Menin interferes with ERK and JNK pathways through two distinct inhibitory mechanisms. Taken together, our data suggest that Menin uncouples ERK and JNK activation from phosphorylation of their nuclear targets Elk-1, JunD and c-Jun, hence inhibiting accumulation of active Fos/Jun heterodimers. This study provides new molecular insights into the tumor suppressor function of Menin and suggests a mechanism by which Menin may interfere with Ras-dependent cell transformation and oncogenesis.

Original languageEnglish
Pages (from-to)6434-6445
Number of pages12
JournalOncogene
Volume21
Issue number42
DOIs
StatePublished - 2002
Externally publishedYes

Keywords

  • AP-1
  • Elk-1
  • JunD
  • MAPK
  • Menin

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