Subcellular compartments within eukaryotic cells must each be supplied with unique sets of proteins that must be directed to, and translocated across one or more membranes of the target organelles. This transport is mediated by cis- acting targeting signals present within the imported proteins. The following is a chronological account of a series of experiments designed and carried out in an effort to understand how proteins are targeted to the peroxisomal compartment.-We demonstrated by immunocryoelectron microscopy that the enzyme luciferase is a peroxisomal enzyme in the firefly lantern.
-We expressed the cDNA encoding firefly luciferase in mammalian cells and demonstrated by immunofluorescence that the enzyme was transported into the peroxisomes of the transfected cells.
-Using deletions, linker insertions, and gene fusion to identify regions of luciferase involved in its transport to the peroxisomes, we demonstrated that luciferase contains a peroxisomal targeting signal (PTS) within its COOH-terminal twelve amino acid.