Related Experiment Video
Updated: Jun 12, 2025

Assays for the Degradation of Misfolded Proteins in Cells
Published on: August 28, 2016
PLK2-mediated phosphorylation of SQSTM1 S349 promotes aggregation of polyubiquitinated proteins upon proteasomal
Yun-Da Chen1,2,3, Xiu-Ping Lin1,2,3, Zi-Lun Ruan1,2,3
1Department of Infectious Diseases, Medical Research Institute, Zhongnan Hospital of Wuhan University, College of Life Sciences, Wuhan, China.
Abstract:
Dysregulation in protein homeostasis results in accumulation of protein aggregates, which are sequestered into dedicated insoluble compartments so-called inclusion bodies or aggresomes, where they are scavenged through different mechanisms to reduce proteotoxicity. The protein aggregates can be selectively scavenged by macroautophagy/autophagy called aggrephagy, which is mediated by the autophagic receptor SQSTM1. In this study, we have identified PLK2 as an important regulator of SQSTM1-mediated aggregation of polyubiquitinated proteins. PLK2 is upregulated following proteasome inhibition, and then associates with and phosphorylates SQSTM1 at S349. The phosphorylation of SQSTM1 S349 strengthens its binding to KEAP1, which is required for formation of large SQSTM1 aggregates/bodies upon proteasome inhibition. Our findings suggest that PLK2-mediated phosphorylation of SQSTM1 S349 represents a critical regulatory mechanism in SQSTM1-mediated aggregation of polyubiquitinated proteins.
Related Concept Videos
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...
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...
Covalently Linked Protein Regulators
These groups modify specific amino acids in a protein....
Destabilization of Microtubules
PI3K/mTOR/AKT Signaling Pathway
Export of Misfolded Proteins out of the ER

