Deubiquitinase involved in innate antiviral immunity by mediating deubiquitination of CGAS and DDX58/RIG-I (PubMed:31534008). Negatively regulates DDX58/RIG-I by mediating 'Lys-63'-linked deubiquitination of DDX58/RIG-I, inhibiting type I interferon signaling (By similarity). Also regulates 'Lys-63'-linked ubiquitination level of MDA5/IFIH1 (By similarity). Acts as a positive regulator of the cGAS-STING pathway by catalyzing 'Lys-48'-linked deubiquitination of CGAS, thereby promoting its stabilization (PubMed:31534008). Can reduce the levels of BCL2L11/BIM ubiquitination and stabilize BCL2L11 in response to the RAF-MAPK-degradation signal (PubMed:27013495). By acting on BCL2L11 levels, may counteract the anti-apoptotic effects of MAPK activity (PubMed:27013495). Thiol-dependent hydrolysis of ester, thioester, amide, peptide and isopeptide bonds formed by the C-terminal Gly of ubiquitin (a 76-residue protein attached to proteins as an intracellular targeting signal). Interacts with phosphorylated BCL2L11 isoform BIMEL; this interaction leads to BCL2L11 deubiquitination and stabilization. Belongs to the peptidase C19 family. Although strongly related to USP22, which deubiquitinates histones, lacks the N-terminal UBP-type zinc finger, suggesting it does not have the ability to deubiquitinate histones. Extended N-terminus.