Related Experiment Video
Updated: Jun 7, 2026

Detection of Protein Ubiquitination Sites by Peptide Enrichment and Mass Spectrometry
Published on: March 23, 2020
A data set of human endogenous protein ubiquitination sites
Yi Shi1, Doug W Chan, Sung Yun Jung
1Center for Molecular Discovery, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA.
Abstract:
Lysine ubiquitination is an important and versatile protein post-translational modification. Numerous cellular functions are regulated by ubiquitination, suggesting that extensive numbers of proteins, if not all, are modified with ubiquitin at certain times. However, proteome-wide profiling of ubiquitination sites in the mammalian system is technically challenging. We report the design and characterization of an engineered protein affinity reagent for the isolation of ubiquitinated proteins and the identification of ubiquitination sites with mass spectrometry. This recombinant protein consists of four tandem repeats of ubiquitin-associated domain from UBQLN1 fused to a GST tag. We used this GST-qUBA reagent to isolate polyubiquitinated proteins and identified 294 endogenous ubiquitination sites on 223 proteins from human 293T cells without proteasome inhibitors or overexpression of ubiquitin. Mitochondrial proteins constitute 14.7% of this data set, implicating ubiquitination in a wide range of mitochondrial functions.
Related Concept Videos
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein.
The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. This involves participation of a series of enzymes including— E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3 (ubiquitin...
The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
The Proteasome Structure
The proteasome is an...
Regulated Protein Degradation
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...

