Glutamylase that mediates the covalent attachment of glutamate moieties to SdeA on one of the catalytic residues that is required for its mono-ADP-ribosyltransferase activity (PubMed:31330532, PubMed:31330531). In turn, inhibits SdeA ubiquitinating activity. Glutamylates also related SdeB, SdeC and SidE (PubMed:31330531, PubMed:31123136). Glutamylase activity only occurs in the host since it requires host calmodulin (PubMed:28497808, PubMed:31330532, PubMed:31330531, PubMed:31123136). May also reverse the SdeA-mediated substrate ubiquitination by cleaving the phosphodiester bond that links phosphoribosylated ubiquitin to protein substrates via its deubiquitinase activity (PubMed:28497808). ATP + L-glutamate + L-glutamyl-[protein] = ADP + gamma-L-glutamyl-L-glutamyl-[protein] + H(+) + phosphate (L-glutamyl)(n)-gamma-L-glutamyl-L-glutamyl-[protein] + ATP + L-glutamate = (L-glutamyl)(n+1)-gamma-L-glutamyl-L-glutamyl-[protein] + ADP + H(+) + phosphate Glytamylation catalyzed by SidJ requires host calmodulin and can be regulated by intracellular changes in Ca2+ concentrations. Requires also ATP. Interacts with host calmodulin/CALM1; this interaction is required for glutamylase activity.