RRC ID 57054
Author Watanabe S, Fujiyama H, Takafuji T, Kayama K, Matsumoto M, Nakayama KI, Yoshida K, Sugimoto N, Fujita M.
Title GRWD1 regulates ribosomal protein L23 levels via the ubiquitin-proteasome system.
Journal J Cell Sci
Abstract Glutamate-rich WD40 repeat-containing 1 (GRWD1) is a Cdt1-binding protein that promotes mini-chromosome maintenance (MCM) loading through its histone chaperone activity. GRWD1 acts as a tumor-promoting factor by downregulating p53 (also known as TP53) via the RPL11-MDM2-p53 axis. Here, we identified GRWD1-interacting proteins using a proteomics approach and showed that GRWD1 interacts with various proteins involved in transcription, translation, DNA replication and repair, chromatin organization, and ubiquitin-mediated proteolysis. We focused on the ribosomal protein ribosomal protein L23 (RPL23), which positively regulates nucleolar stress responses through MDM2 binding and inhibition, thereby functioning as a tumor suppressor. Overexpression of GRWD1 decreased RPL23 protein levels and stability; this effect was restored upon treatment with the proteasome inhibitor MG132. EDD (also known as UBR5), an E3 ubiquitin ligase that interacts with GRWD1, also downregulated RPL23, and the decrease was further enhanced by co-expression of GRWD1. Conversely, siRNA-mediated GRWD1 knockdown upregulated RPL23. Co-expression of GRWD1 and EDD promoted RPL23 ubiquitylation. These data suggest that GRWD1 acts together with EDD to negatively regulate RPL23 via the ubiquitin-proteasome system. GRWD1 expression reversed the RPL23-mediated inhibition of anchorage-independent growth in cancer cells. Our data suggest that GRWD1-induced RPL23 proteolysis plays a role in downregulation of p53 and tumorigenesis.
Volume 131(15)
Published 2018-8-3
DOI 10.1242/jcs.213009
PII jcs.213009
PMID 29991511
MeSH Carrier Proteins / metabolism* HEK293 Cells Humans Leupeptins / pharmacology Proteasome Endopeptidase Complex / drug effects Proteasome Endopeptidase Complex / metabolism* Protein Binding / drug effects Ribosomal Proteins / metabolism* Ubiquitin / metabolism Ubiquitin-Protein Ligases / metabolism Ubiquitination / drug effects
IF 4.517
Times Cited 5
DNA material pFLAG-CMV-5a-RPL23 (RDB17324) pGEX6P-1-RPL23 (RDB17325) pET-28a-RPL23 (RDB17326) pCLH'CX-His-T7-RPL23 (RDB17327) pCMV-GRWD1 (RDB17328)