SUMO-specific isopeptidase USPL1 (USPL1)

SUMO-specific isopeptidase USPL1 (USPL1) is an atypical member of the ubiquitin-specific protease (USP) family, but unlike other USPs, it functions as a SUMO protease rather than a deubiquitinase. USPL1 specifically binds and cleaves SUMO2 and SUMO3 proteins, regulating the removal of SUMO (Small Ubiquitin-like Modifier) from target substrates[2][4][6]. USPL1 is essential for the integrity of Cajal bodies in the nucleus, where it directly associates with U snRNA gene loci and interacts with the Little Elongation Complex to regulate transcription of snRNAs by RNA polymerase II[2][4]. Disruption of USPL1 leads to defects in snRNA expression, snRNP assembly, and pre-mRNA splicing, ultimately compromising cell growth and proliferation[4]. Genetic variants in USPL1 can affect breast cancer risk, and its dysregulation may modulate tumor progression, but it is not currently targeted by any approved drugs[4]. Structurally, USPL1 contains a USP-like catalytic core adapted for SUMO cleavage and unique features that distinguish it from canonical USPs[2][6].

Other names

C13orf22D13S106D13S106EbA121O19.1USP-like 1ubiquitin-specific peptidase-like protein 1highly charged protein