During DNA replication, the deubiquitinating enzyme USP1 limits the recruitment of translesion polymerases by removing ubiquitin marks from PCNA to allow specific regulation of the translesion synthesis (TLS) pathway. USP1 activity depends on an allosteric activator, UAF1, and this is tightly controlled. In comparison to paralogs USP12 and USP46, USP1 contains three defined inserts and lacks the second WDR20-mediated activation step. Here we show how inserts L1 and L3 together limit intrinsic USP1 activity and how this is relieved by UAF1. Intriguingly, insert L1 also conveys substrate-dependent increase in USP1 activity through DNA and PCNA interactions, in a process that is independent of UAF1-mediated activation. This study establishes insert L1 as an important regulatory hub within USP1 necessary for both substrate-mediated activity enhancement and allosteric activation upon UAF1 binding.
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http://dx.doi.org/10.15252/embr.202051749 | DOI Listing |
Nat Commun
December 2024
Center for Genomic Integrity, Institute for Basic Science, Ulsan, 44919, Republic of Korea.
Blood Cancer J
November 2024
Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA.
Internal tandem duplications (ITD) in fms-like tyrosine kinase 3 (FLT3) represent the most common genetic alteration in de novo acute myeloid leukemia (AML). Here, we identify ribosomal protein s6 kinase a1 (RSK1) as a core dependency in FLT3-ITD AML and unveil the existence of crucial bi-directional regulation. RSK1 perturbation resulted in marked apoptosis and abrogated phosphorylation of FLT3 and associated downstream signaling cascades in FLT3-ITD AML cell lines.
View Article and Find Full Text PDFSci Adv
November 2024
Molecular Oncology Unit, Centro di Riferimento Oncologico di Aviano (CRO) IRCCS, National Cancer Institute, Aviano (PN), Italy.
PARP inhibitors (PARPi) represent a game-changing treatment for patients with ovarian cancer with tumors deficient for the homologous recombination (HR) pathway treated with platinum (Pt)-based therapy. PARPi exert their cytotoxic effect by both trapping PARP1 on the damaged DNA and by restraining its enzymatic activity (PARylation). How PARP1 is recruited and trapped at the DNA damage sites and how resistance to PARPi could be overcome are still matters of investigation.
View Article and Find Full Text PDFCells
October 2024
Department of Laboratory Medicine, School of Medicine, Hunan Normal University, Changsha 410013, China.
Background: Ubiquitination is an important post-transcriptional modification crucial for maintaining cell homeostasis. As a deubiquitination enzyme, ubiquitin-specific protease 1 (USP1) is associated with tumor progression; however, its role in bladder cancer is unknown. This study aimed to analyze USP1 expression and study its roles in bladder cancer.
View Article and Find Full Text PDFAnn Transl Med
October 2024
Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, LA, USA.
Background And Objective: The nuclear factor kappa B (NF-κB) consists of a group of transcription factors of which its dysregulation is responsible for diseases such as inflammation and cancer. Ubiquitin-specific proteases (USPs) are the most prominent group among the deubiquitinases (DUBs). Their functions include control of protein stability and regulation of signaling transduction.
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