From evolution to function: Two sides of the same CENP-B coin?

The centromere is the nucleoproteic chromosomal structure necessary for accurate chromosome segregation during cell division. One of the earliest centromeric proteins to be discovered was CENP-B, the only one capable of recognizing a specific centromeric DNA binding motif. The phylogenetic history of this protein and of its DNA binding site shows independent events of function acquisition across different species and raises questions on the evolutionary dynamics of CENP-B, including what may be the selective advantage provided by its role at the centromere. Recent results have provided insight into potential functions of CENP-B in chromosome dynamics, however, its function is still object of debate. The recurrent appearance of CENP-B centromeric activity along phylogenesis, together with its dispensability, represent strictly intertwined facets of this controversy. This chapter focuses on the evolution, function and homeostasis of CENP-B and its importance in centromere biology.