Regulation of the ER-bound transcription factor Luman/CREB3 in HEK293 cells

FEBS Lett. 2019 Oct;593(19):2771-2778. doi: 10.1002/1873-3468.13535. Epub 2019 Jul 21.

Abstract

CREB3 is a transcription factor localized to the ER. Here, we investigated endogenous CREB3 expression in HEK293 cells using pharmacological and genome editing approaches. Full-length CREB3 detected under resting conditions disappeared following treatment with tunicamycin, brefeldin A and nigericin. Treatment with cycloheximide and MG132 indicated that endogenous CREB3 is a proteasome substrate. Using cells deficient for the ER-associated protein degradation (ERAD) factors SEL1L and Herp, we demonstrate that SEL1L, but not Herp, plays a crucial role in the posttranslational regulation of full-length CREB3 expression. In addition, kifunensine, an α-mannosidase inhibitor, remarkably increased full-length CREB3 expression. Our study suggests that endogenous full-length CREB3 is a novel substrate for ERAD and identifies unique cellular signals distinct from those in canonical ER stress.

Keywords: CREB3; ERAD; Herp; SEL1L.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Brefeldin A / pharmacology
  • Cyclic AMP Response Element-Binding Protein / genetics*
  • Cyclic AMP Response Element-Binding Protein / metabolism
  • Cycloheximide / pharmacology
  • Cysteine Proteinase Inhibitors / pharmacology
  • Endoplasmic Reticulum / drug effects
  • Endoplasmic Reticulum / metabolism
  • HEK293 Cells
  • Humans
  • Leupeptins / pharmacology
  • Membrane Proteins / genetics
  • Membrane Proteins / metabolism
  • Nigericin / pharmacology
  • Proteasome Endopeptidase Complex / metabolism*
  • Protein Synthesis Inhibitors / pharmacology
  • Proteins / genetics
  • Proteins / metabolism
  • Tunicamycin / pharmacology

Substances

  • CREB3 protein, human
  • Cyclic AMP Response Element-Binding Protein
  • Cysteine Proteinase Inhibitors
  • HERPUD1 protein, human
  • Leupeptins
  • Membrane Proteins
  • Protein Synthesis Inhibitors
  • Proteins
  • SEL1L protein, human
  • Tunicamycin
  • Brefeldin A
  • Cycloheximide
  • Proteasome Endopeptidase Complex
  • benzyloxycarbonylleucyl-leucyl-leucine aldehyde
  • Nigericin