Related Experiment Video
Updated: Feb 21, 2026

In Vitro Analysis of E3 Ubiquitin Ligase Function
Published on: May 14, 2021
Ubiquitin-Conjugating Enzyme E2 L3 is Downregulated by the Chikungunya Virus nsP2 Protease
Suwipa Ramphan1, Sarawut Khongwichit1, Chonticha Saisawang1
1Institute of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand.
Purpose:
Chikungunya virus (CHIKV) is a mosquito transmitted alphavirus that causes chikungunya fever in humans. The CHIKV non-structural protein 2 (nsP2) is a multifunctional protein that additionally modulates the host cell to dampen the innate immune response and inhibit other cellular processes.
Experimental Design:
To further investigate the interactions of nsP2 with host cells, the protease domain of CHIKV nsP2 (nsP2-pro) is transfected into Hela cells, and differential protein expression is detected by 2D polyacrylamide gel electrophoresis.
Results:
A total of 21 differentially regulated (six upregulated, 15 downregulated) spots are observed, of which five are identified by mass spectrometry. The downregulation of one of the identified proteins, ubiquitin-conjugating enzyme E2 L3 (UBE2L3) is confirmed by western blotting of both nsP2-pro transfection and CHIKV natural infection, and the downregulation of UBE2L3 is additionally shown to require an enzymatically active nsP2 protease domain. Transfection of full length UBE2L3 into HEK293T/17 cells prior to CHIKV infection reduce levels of infection and E protein expression but do not alter RNA genome levels.
Conclusion:
These results suggest that UBE2L3 is a cellular target of the CHIKV nsP2 protease, and this possibly mediates the pathogenesis of chikungunya fever.
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...
Receptor Downregulation in MVBs
The EGFR can initiate signaling pathways that lead to cell proliferation, migration, and differentiation. Overexpression of EGFR stimulates cells to proliferate. Excessive EGFR...
The Unfolded Protein Response
Export of Misfolded Proteins out of the ER
Regulation of the Unfolded Protein Response
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...

