Ubiquitin-specific protease that deubiquitinates target proteins to regulate different cellular and developmental pathways (PubMed:10949024, PubMed:18160715, PubMed:26169834, PubMed:27552662). Functions downstream of Dsor1/MEK to positively regulate the Ras/MAPK signaling pathway (PubMed:27552662). Likely to modulate the pathway during various cellular and developmental processes including rl/MAPK activation by the receptors InR, Egfr and sevenless/sev (PubMed:27552662). Functions in the post-translational stabilization of rl/MAPK levels in a mechanism that is independent of rl activity and opposes the activity of the E2 enzyme Unc6 and the putative E3 ligases poe, Ufd4 and Kcmf1, which mediate the ubiquitination and proteasomal degradation of rl (PubMed:27552662). During eye development it may also act downstream of rl/MAPK to negatively regulate the Ras/MAPK signaling pathway by stabilizing the transcriptional repressor ttk and consequently inhibiting photoreceptor cell development (PubMed:18160715). This suggests that at least during eye development, it may act in both the positive and negative regulation of the Ras/MAPK signaling pathway to mediate the development of different cell types (PubMed:18160715, PubMed:27552662). Positively regulates border follicle cell migration during oogenesis by mediating the deubiquitination and stabilization of slbo (PubMed:10949024). In the wing disks it positively regulates wg signaling by stabilizing arm (PubMed:26169834). Has an effect on position-effect variegation (PubMed:8816485). 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 ttk. Ubiquitously expressed in the embryo (at protein level). Ubiquitously expressed in the developing eye (at protein level). RNAi-mediated knockdown in the adult wing results in the development of wing margin bristles (PubMed:26169834). RNAi-mediated knockdown in the posterior compartment of the wing reduces accumulation of arm, resulting in reduced expression of sens and wg (PubMed:26169834). RNAi-mediated knockdown in larval wing or eye imaginal disks results in decreased rl protein levels (PubMed:27552662). Belongs to the peptidase C19 family. Truncated N-terminus. Truncated N-terminus.