Secreted effector that interferes with the host cell ubiquitin pathway and is required for intracellular bacterial replication. Catalyzes the ubiquitination of several mammalian Rab proteins (Rab33b, Rab1, Rab6a and Rab30) during L.pneumophila infection, without engaging the standard cellular enzyme cascade (E1 and E2) (PubMed:29795346). Transfers an ADP-ribose moiety from NAD to the 'Arg-42' residue of ubiquitin in a reaction that releases nicotinamide (PubMed:31330532, PubMed:31330531, PubMed:29795347). The modified ubiquitin is subsequently transferred to serine residues of the substrate protein via a phosphoribose linker that results in the release of AMP (PubMed:27912065). Cannot ubiquitinate the endosomal Rab5 or the cytoskeletal small GTPase Rac1 (PubMed:27049943). Also acts as a deubiquitinase (DUB), catalyzing the cleavage of three of the most abundant polyubiquitin chains ('Lys-11', 'Lys-48' and 'Lys-63') with a distinct preference for 'Lys-63' linkages; is thus able to efficiently remove 'Lys-63'-linked polyubiquitin chains from the phagosomal surface. Is also able to remove NEDD8 from neddylated proteins, but is unable to recognize SUMO. The DUB activity of SdeA is important for regulating the dynamics of ubiquitin association with the bacterial phagosome, but is dispensable for its role in intracellular bacterial replication (PubMed:26598703). L-arginyl-[protein] + NAD(+) = H(+) + N(omega)-(ADP-D-ribosyl)-L-arginyl-[protein] + nicotinamide Ubiquitination catalyzed by SdeA is insensitive to the cysteine alkylation agent maleimide, suggesting that a cysteine conjugation of ubiquitin does not form during the reaction. Interacts with IcmS. Translocated across the phagosomal membrane into host macrophages via the Dot/Icm type IV secretion system (T4SS) in an IcmS-dependent manner. Appears to localize to the cytoplasmic face of the Legionella-containing vacuole (LCV) in the early stages of infection. Expression is induced during the transition from exponential to stationary phase. Contains an N-terminal deubiquitinase domain (DUB) (PubMed:26598703). The DUB domain does not interfere with the ubiquitin conjugation activity catalyzed by the central domain of SdeA, which causes toxicity (PubMed:27049943). Is able to ubiquitinate itself, but this modification is not required to ubiquitinate Rab33b. Glutamylated at Glu-860 by SidJ; glutamylation inhibits SdeA activity to catalyze the production of ADP-ribosylated ubiquitin. Cells lacking all four members of the SidE family (SdeA, SdeB, SdeC and SidE) show no intracellular growth defect in mouse bone marrow macrophages (BMM), but display attenuated growth inside the protozoan hosts A.castellanii and D.discoideum (PubMed:15773981, PubMed:27049943). This mutant no longer recruits the endoplasmic reticulum (ER) marker GFP-HDEL to its vacuoles, even at 10 hours post infection, and is unable to induce Rab33b ubiquitination during infection (PubMed:27049943). The rate of ubiquitin-positive Legionella-containing vacuoles increases from 40% (wild-type) to approximately 90% in infections using the SidE family deletion mutant strain (PubMed:26598703). All these defects can be completely complemented by expressing sdeA on a plasmid (PubMed:15773981, PubMed:27049943, PubMed:26598703). Belongs to the SidE family. Extended N-terminus.