Ubiquitin carboxyl-terminal hydrolase 1 is an enzyme that in humans is encoded by the USP1 gene.
This gene encodes a member of the ubiquitin-specific processing (UBP) family of proteases that is a deubiquitinating enzyme (DUB) with His and Cys domains. This protein is located in the cytoplasm and cleaves the ubiquitin moiety from ubiquitin-fused precursors and ubiquitinylated proteins.
The protein specifically deubiquitinates a protein in the Fanconi anemia (FA) DNA repair pathway. Alternate transcriptional splice variants have been characterized.
UCH-L1 has been studied, in a 2020 paper by Sharma, et al for its association with neurodegenerative diseases (Parkinson's disease)
A 2024 paper by Li, et al indicates possible contribution to cancer progression. Apparently via stabilizing proteins that promote cell proliferation (in TNBC, UCHL1 deubiquitinates and stabilizes KLF5, as a consequence there is resistance to endocrine therapy).