ADEPTs: information necessary for subcellular distribution of eukaryotic sorting isozymes resides in domains missing from eubacterial and archaeal counterparts

Sorting isozymes are encoded by single genes, but the encoded proteins are distributed to multiple subcellular compartments. We surveyed the predicted protein sequences of several nucleic acid interacting sorting isozymes fro m the eukaryotic taxonomic domain and compared them with their homologs in the archaeal and eubacterial domains. Here, we summarize the data showing t hat the eukaryotic sorting isozymes often possess sequences not present in the archaeal and eubacterial counterparts and that the additional sequences can act to target the eukaryotic proteins to their appropriate subcellular locations. Therefore, we have named these protein domains ADEPTs (Addition al Domains for Eukaryotic Protein Targeting). Identification of additional domains by phylogenetic comparisons should be generally useful for locating candidate sequences important for subcellular distribution of eukaryotic p roteins.