Related Experiment Videos

Glycogen synthase kinase 3 regulates expression of nuclear factor-erythroid-2 related transcription factor-1 (Nrf1)

Madhurima Biswas1, Erick K Kwong1, Eujean Park1

  • 1Department of Laboratory Medicine and Pathology, University of California, Irvine, D440 Medical Science 1, Irvine, CA 92697, USA.

Experimental Cell Research
|April 30, 2013
PubMed

Insights

Glycogen synthase kinase 3 (GSK3) targets Nuclear factor E2-related factor-1 (Nrf1) for degradation, impacting cell survival. Stabilizing Nrf1 with a mutation reduces apoptosis during cellular stress.

Area of Science:

  • Molecular Biology
  • Cellular Biology
  • Biochemistry

Background:

  • Nuclear factor E2-related factor-1 (Nrf1) is a transcription factor regulating antioxidant and cytoprotective genes.
  • Nrf1 degradation is known to be mediated by the SCF-Fbw7 ubiquitin ligase.
  • Upstream signals targeting Nrf1 for degradation remain largely unknown.

Purpose of the Study:

  • To investigate the upstream regulators of Nrf1 degradation.
  • To elucidate the role of glycogen synthase kinase 3 (GSK3) in Nrf1 regulation.
  • To understand the impact of GSK3-mediated Nrf1 regulation on neuronal cell survival under stress.

Main Methods:

  • Co-immunoprecipitation to assess GSK3-Nrf1 interaction.
  • Site-directed mutagenesis to create phosphorylation-resistant Nrf1 (S350A).
  • Neuronal cell culture, Western blotting, and apoptosis assays (e.g., TUNEL).

Main Results:

  • GSK3 directly interacts with and phosphorylates Nrf1 at the Cdc4 phosphodegron domain (CPD).
  • Mutation of the phosphorylation site (S350A) stabilizes Nrf1 and prevents GSK3-mediated degradation.
  • GSK3 inhibition or Nrf1 knockdown increases neuronal apoptosis under ER stress; S350A-Nrf1 expression attenuates this apoptosis.

Conclusions:

  • GSK3 negatively regulates Nrf1 expression through Fbw7-dependent degradation.
  • GSK3-mediated regulation of Nrf1 is critical for neuronal cell survival during ER stress.
  • Targeting the GSK3-Nrf1 pathway may offer therapeutic strategies for neurodegenerative diseases involving stress-induced apoptosis.
Keywords:
ARECNC-BZIPCNC-bZIPCPDCap ‘n’ Collar-type basic leucine zipperCdc4 phosphodegron domainERFbw7GSK3Nrf1Nuclear factor E2-related factor-1SCFSkp1–Cul1–F-boxStress responseTranscription factorUPSantioxidant response elementendoplasmic reticulumglycogen synthase kinase 3nuclear factor E2-related factor-1ubiquitin proteasome system

Related Concept Videos

NF-κB-dependent Signaling Pathway02:26

NF-κB-dependent Signaling Pathway

The transcription factor NF-κB was discovered in 1986 in the lab of Nobel laureate Professor David Baltimore, for its interaction with the immunoglobulin light chain enhancer in B-cells. After more than three decades of study, it is now evident that NF-κB regulates the expression of over 100 genes. Most of these genes play an essential role in the innate and adaptive immune responses as well as the inflammatory responses of animals.
NF-κB-dependent Signaling Mechanism
The heterodimer of NF-κB...
Regulation of Nuclear Protein Sorting01:45

Regulation of Nuclear Protein Sorting

Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
mTOR Signaling and Cancer Progression03:03

mTOR Signaling and Cancer Progression

The mammalian target of rapamycin or mTOR protein was discovered in 1994 due to its direct interaction with rapamycin. The protein gets its name from a yeast homolog called TOR. The mTOR protein complex in mammalian cells plays a major role in balancing anabolic processes such as the synthesis of proteins, lipids, and nucleotides and catabolic processes, such as autophagy in response to environmental cues, such as availability of nutrients and growth factors.
The mTOR pathway or the...
Negative Regulator Molecules01:23

Negative Regulator Molecules

Positive regulators allow a cell to advance through cell cycle checkpoints. Negative regulators have an equally important role as they terminate a cell’s progression through the cell cycle—or pause it—until the cell meets specific criteria.