Internal ribosome entry site-mediated translational regulation of ATF4 splice variant in mammalian unfolded protein response

Ching Ping Chan, Kin Hang Kok, Hei Man Vincent Tang, Chi Ming Wong, Dong Yan Jin

Research output: Journal article publicationJournal articleAcademic researchpeer-review

27 Citations (Scopus)

Abstract

Activating transcription factor 4 (ATF4) is a master regulator of genes involved in unfolded protein response (UPR) and its translation is regulated through reinitiation at upstream open reading frames. Here, we demonstrate internal ribosome entry site (IRES)-mediated translation of an alternatively spliced variant of human ATF4. This variant that contains four upstream open reading frames in the 5' leader region was expressed in leukocytes and other tissues. mRNA and protein expression of this variant was activated in the UPR. Its translation was neither inhibited by steric hindrance nor affected by eIF4G1 inactivation, indicating a cap-independent and IRES-dependent mechanism not mediated by ribosome scanning-reinitiation. The IRES activity mapped to a highly structured region that partially overlaps with the third and fourth open reading frames was unlikely attributed to cryptic promoter or splicing, but was activated by PERK-induced eIF2α phosphorylation. Taken together, our findings reveal a new mechanism for translational regulation of ATF4 in mammalian UPR.
Original languageEnglish
Pages (from-to)2165-2175
Number of pages11
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1833
Issue number10
DOIs
Publication statusPublished - 1 Oct 2013
Externally publishedYes

Keywords

  • ATF4
  • EIF2α
  • Internal ribosome entry site (IRES)
  • Translation initiation
  • Unfolded protein response
  • Upstream open reading frame

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology

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