Protein splicing and its evolution in eukaryotes

Abstract

Inteins, or protein introns, are parts of protein sequences that are post-translationally excised, their flanking regions (exteins) being spliced together. This process was called protein splicing. Originally inteins were found in prokaryotic or unicellular eukaryotic organisms. But the general principles of post-translation protein rearrangement are evolving yielding different post-translation modification of proteins in multicellular organisms. For clarity, these non-intein mediated events call either protein rearrangements or protein editing. The most intriguing example of protein editing is proteasome-mediated splicing of antigens in vertebrates that may play important role in antigen presentation. Other examples of protein rearrangements are maturation of Hg-proteins (critical receptors in embryogenesis) as well as maturation of several metabolic enzymes. Despite a lack of experimental data we try to analyze some intriguing examples of protein splicing evolution.