An evolutionary perspective on the origin, conservation and binding partner acquisition of tankyrases

Tankyrases are poly-ADP-ribosyltransferases that regulate many crucial and diverse cellular processes in humans such as Wnt signaling, telomere homeostasis, mitotic spindle formation and glucose metabolism. While tankyrases are present in most animals, functional differences across species exist. In this work we confirm the widespread distribution of tankyrases throughout the branches of multicellular animal life and identified the single-celled choanoflagellates as earliest origin of tankyrases. We further show that sequence and structural aspects of TNKSs are well conserved even between highly diverged species. We also experimentally characterized an anciently diverged tankyrase homolog from the sponge Amphimedon queenslandica and show that the basic functional aspects, such as poly-ADP-ribosylation activity and interaction with the canonical tankyrase binding peptide motif, are conserved. Conversely, the presence of tankyrase binding motifs in orthologs of confirmed interaction partners vary greatly between species, indicating that tankyrases have different sets of interaction partners depending on the animal lineage. Overall, our analysis suggests a remarkable degree of conservation for tankyrases, although their regulatory functions in cells have likely changed considerably throughout evolution.