Related Experiment Video

Updated: Sep 19, 2025

Identification of Novel CK2 Kinase Substrates Using a Versatile Biochemical Approach
11:11

Identification of Novel CK2 Kinase Substrates Using a Versatile Biochemical Approach

Published on: February 21, 2019

7.5K

Targeted O-GlcNAcylation of CK2α Triggers Its Ubiquitin-Proteasome Degradation and Alters Downstream Phosphorylation

Tongyang Xu1, Bowen Ma1, Yuanpei Li1

  • 1Guangdong-Hong Kong-Macao Joint Laboratory for New Drug Screening, School of Pharmacy, The Chinese University of Hong Kong, Sha Tin, Hong Kong.

ACS Chemical Biology
|June 16, 2025
PubMed

Insights

O-Linked N-acetylglucosamine-modification (O-GlcNAcylation) of casein kinase II subunit α (CK2α) destabilizes the protein via proteasomal degradation. This targeted modification reveals O-GlcNAcylation

Area of Science:

  • Biochemistry
  • Molecular Biology
  • Chemical Biology

Background:

  • O-Linked N-acetylglucosamine-modification (O-GlcNAcylation) is a crucial post-translational modification (PTM) involved in various cellular processes.
  • Dissecting the specific functions of O-GlcNAcylation on individual proteins has been a significant challenge in the field.

Purpose of the Study:

  • To investigate the protein-specific functions of O-GlcNAcylation using a targeted chemical biology approach.
  • To elucidate the impact of O-GlcNAcylation on the stability and function of casein kinase II subunit α (CK2α).

Main Methods:

  • Utilized a chemical biology tool, O-GlcNAcylation Targeting Chimera (OGTAC), to specifically induce O-GlcNAcylation of CK2α at Ser347 in living cells.
  • Employed overexpression and knockdown experiments to analyze the role of CK2α in the CRL4CRBN E3 ligase complex.
  • Investigated the downstream effects of targeted O-GlcNAcylation on Akt and PFKP phosphorylation.

Main Results:

  • Targeted O-GlcNAcylation of CK2α at Ser347 led to its destabilization through ubiquitin-proteasome degradation.
  • O-GlcNAcylation enhanced the interaction between CK2α and cereblon (CRBN).
  • CK2α was identified as a substrate of the CRL4CRBN E3 ligase complex.
  • O-GlcNAcylation of CK2α reprogrammed the phosphorylation of downstream targets Akt and PFKP.

Conclusions:

  • A single O-GlcNAc modification can act as a molecular switch, controlling protein stability and downstream signaling pathways.
  • The OGTAC tool provides a specific and effective method to study O-GlcNAcylation functions, overcoming limitations of global perturbation methods.

More Related Videos

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay12:26

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

18.8K
Oligopeptide Competition Assay for Phosphorylation Site Determination09:16

Oligopeptide Competition Assay for Phosphorylation Site Determination

Published on: May 18, 2017

8.5K

Related Concept Videos

Regulated Protein Degradation02:58

Regulated Protein Degradation

It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
7.7K
Covalently Linked Protein Regulators02:04

Covalently Linked Protein Regulators

Proteins can undergo many types of post-translational modifications, often in response to changes in their environment. These modifications play an important role in the function and stability of these proteins. Covalently linked molecules include functional groups, such as methyl, acetyl, and phosphate groups, and also small proteins, such as ubiquitin. There are around 200 different types of covalent regulators that have been identified.
These groups modify specific amino acids in a protein....
7.5K
Protein Kinases and Phosphatases02:54

Protein Kinases and Phosphatases

Proteins undergo chemical modifications that trigger changes in the charge, structure, and conformation of the proteins. Phosphorylation, acetylation, glycosylation, nitrosylation, ubiquitination, lipidation, methylation, and proteolysis are various protein modifications that regulate protein activity. Such modifications are usually enzyme-driven.
Protein kinases
Many proteins in the cell are regulated by phosphorylation, the addition of a phosphate group. A family of enzymes called kinases...
13.5K
Anaphase Promoting Complex00:50

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
3.0K
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
9.9K
Phosphorylation01:02

Phosphorylation

The addition or removal of phosphate groups from proteins is the most common chemical modification that regulates cellular processes. These modifications can affect the structure, activity, stability, and localization of proteins within cells as well as their interactions with other proteins.
During phosphorylation, protein kinases transfer the terminal phosphate group of ATP to specific amino acid side chains of substrate proteins. Serine, threonine, and tyrosine are the most commonly...
51.3K