TRIM21 suppresses CHK1 activation by preferentially targeting CLASPIN for K63-linked ubiquitination.

Expression of the E3 ligase TRIM21 is increased in a broad spectrum of cancers; however, the functionally relevant molecular pathway targeted by TRIM21 overexpression remains largely unknown. Here, we show that TRIM21 directly interacts with and ubiquitinates CLASPIN, a mediator for ATR-dependent CHK1 activation. TRIM21-mediated K63-linked ubiquitination of CLASPIN counteracts ...
the K6-linked ubiquitination of CLASPIN which is essential for its interaction with TIPIN and subsequent chromatin loading. We further show that overexpression of TRIM21, but not a TRIM21 catalytically inactive mutant, compromises CHK1 activation, leading to replication fork instability and tumorigenesis. Our findings demonstrate that TRIM21 suppresses CHK1 activation by preferentially targeting CLASPIN for K63-linked ubiquitination, providing a potential target for cancer therapy.
Mesh Terms:
Cell Cycle Proteins, Checkpoint Kinase 1, DNA Replication, Protein Kinases, Ubiquitin-Protein Ligases, Ubiquitination
Nucleic Acids Res
Date: Dec. 22, 2021
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