Fig. 5. Targeting of FATP4. (A) Domain architecture of GFP reporter proteins. F4-Nt-GFP contains the first 102 amino acids of mouse FATP4 followed by GFP. LAT-GFP comprises the N-terminal targeting domain (extracellular part, orange box; TMD, light-blue box) of LAT fused to GFP. LAT-ERx-GFP contains the ERx domain of FATP4 (amino acids 47-102, yellow box) inserted into LAT-GFP. (B) The N-terminus of FATP4 is sufficient for the ER localization. Vero cells were transiently transfected with plasmid F4-Nt-GFP and treated for 2 hours with the protein synthesis inhibitor cycloheximide before fixation. Localization to the ER is evidenced by co-distribution with the marker protein lysozyme-myc-KDEL. (C-E) Targeting mediated by the ERx domain. The reporter protein LAT-GFP is localized to the plasma membrane (C). (D,E) Insertion of the 56 amino acids of the ERx domain is sufficient to retain the corresponding LAT-ERx-GFP protein intracellularly. LAT-ERx-GFP is present in the ER (co-distribution with lysozyme-myc-KDEL; D) and in a perinuclear compartment, clearly different from the plasma membrane marked by PLAP (E). Bar, 10 µm.