USP37 deubiquitinates Cdt1 and contributes to regulate DNA replication.
DNA replication control is a key process in maintaining genomic integrity. Monitoring DNA replication initiation is particularly important as it needs to be coordinated with other cellular events and should occur only once per cell cycle. Crucial players in the initiation of DNA replication are the ORC protein complex, marking the origin of replication, and the Cdt1 and Cdc6 proteins, that license these origins to replicate by recruiting the MCM2-7 helicase. To accurately achieve its functions, Cdt1 is tightly regulated. Cdt1 levels are high from metaphase and during G1 and low in S/G2 phases of the cell cycle. This control is achieved, among other processes, by ubiquitination and proteasomal degradation. In an overexpression screen for Cdt1 deubiquitinating enzymes, we isolated USP37, to date the first ubiquitin hydrolase controlling Cdt1. USP37 overexpression stabilizes Cdt1, most likely a phosphorylated form of the protein. In contrast, USP37 knock down destabilizes Cdt1, predominantly during G1 and G1/S phases of the cell cycle. USP37 interacts with Cdt1 and is able to de-ubiquitinate Cdt1 in vivo and, USP37 is able to regulate the loading of MCM complexes onto the chromatin. In addition, downregulation of USP37 reduces DNA replication fork speed. Taken together, here we show that the deubiquitinase USP37 plays an important role in the regulation of DNA replication. Whether this is achieved via Cdt1, a central protein in this process, which we have shown to be stabilized by USP37, or via additional factors, remains to be tested.
Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Ofra s/n, La Laguna, Tenerife, Spain.
Santiago
S
Hernández-Pérez
Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Ofra s/n, La Laguna, Tenerife, Spain.
Elisa
E
Cabrera
Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Ofra s/n, La Laguna, Tenerife, Spain.
Hugo
H
Amoedo
DNA Replication Group, Spanish National Cancer Research Centre (CNIO), E-28029 Madrid, Spain.
Sara
S
Rodríguez-Acebes
Institut Gustave Roussy, 94805 Villejuif, France; Sorbonne Universités, UPMC Univ Paris 06, F-75005 Paris, France; CNRS - UMR 8200, 94805 Villejuif, France.
Stephane
S
Koundrioukoff
Institut Gustave Roussy, 94805 Villejuif, France; Sorbonne Universités, UPMC Univ Paris 06, F-75005 Paris, France; CNRS - UMR 8200, 94805 Villejuif, France.
Michelle
M
Debatisse
DNA Replication Group, Spanish National Cancer Research Centre (CNIO), E-28029 Madrid, Spain.
Juan
J
Méndez
Unidad de Investigación, Hospital Universitario de Canarias, Instituto de Tecnologías Biomédicas, Ofra s/n, La Laguna, Tenerife, Spain. Electronic address: rfreire@ull.edu.es.
Raimundo
R
Freire
D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D004261:DNA Replication; D010450:Endopeptidases / Q000378:metabolism*; D016193:G1 Phase; D006801:Humans; D010766:Phosphorylation; D011485:Protein Binding; D016196:S Phase; D054875:Ubiquitination
C467199:CDT1 protein, human; D018797:Cell Cycle Proteins; D010450:Endopeptidases; C559980:USP37 protein, human
DNA damage; DNA damage response; Initiation of DNA replication; Proteasome; Protein degradation; Ubiquitin hydrolase