Fic-1 is the only Fic protein present in the genetic code of C. elegans. It is primarily found in the ER nuclear envelope of adult germline cells and embryotic cells, but small amounts may be found within the cytoplasm. This extra-ER pool of FICD-1s is credited with AMPylation of core histones and eEF1-A type translation factors within the nematode.
Though varying AMPylation levels did not create any noticeable effects within the nematodes behaviour or physiology, Fic-1 knockout worms were more susceptible to infection by Pseudomonas aeruginosa' compared to the counterparts with active Fic-1 domains, implying a link between AMPylation of cellular targets and immune responses within nematodes.