Immunofluorescence analysis in Neuro2A cells of FLAG-tagged (A) full-length FAM105A protein, (B) the FAM105A1−100 N-Terminus and (C) the FAM105A84−356 OTU domain. Coimmunostaining for endogenous KDEL (green) marked the endoplasmic reticulum. FLAG-FAM105A and FLAG-FAM105A1−100 largely colocalize with KDEL in the cytoplasm, but FLAG-FAM105A84−356 OTU-domain protein appears diffuse throughout the cytoplasm and in puncta within the nucleus. (D) HA-FAM105A, but not (E) the isolated OTU-domain, HA-FAM105A84−356, localizes to the nuclear envelope, which is marked by immunostaining for Lamin B1 (green). All FAM105A proteins are shown in red.