:TRF2 is a complex protein with four functional domains (regions). Okamoto probed the specific functions of these four domains by creating artificial TRF2-like proteins—in which one or more functional domains were replaced with non-functional "dummy" domains. By studying how these artificial TRF2s functioned in cells, he could determine the separate functions of each individual domain."- Read more at: http://medicalxpress.com/news/2013-02-chromosomes-loose.html#jCp-Not a very simple protein. It keeps chromosomes separated.