TY - JOUR T1 - Structural basis of Nrd1–Nab3 heterodimerization JF - Life Science Alliance JO - Life Sci. Alliance DO - 10.26508/lsa.202101252 VL - 5 IS - 4 SP - e202101252 AU - Belén Chaves-Arquero AU - Santiago Martínez-Lumbreras AU - Sergio Camero AU - Clara M Santiveri AU - Yasmina Mirassou AU - Ramón Campos-Olivas AU - Maria Ángeles Jiménez AU - Olga Calvo AU - José Manuel Pérez-Cañadillas Y1 - 2022/04/01 UR - https://www.life-science-alliance.org/content/5/4/e202101252.abstract N2 - Heterodimerization of RNA binding proteins Nrd1 and Nab3 is essential to communicate the RNA recognition in the nascent transcript with the Nrd1 recognition of the Ser5-phosphorylated Rbp1 C-terminal domain in RNA polymerase II. The structure of a Nrd1–Nab3 chimera reveals the basis of heterodimerization, filling a missing gap in knowledge of this system. The free form of the Nrd1 interaction domain of Nab3 (NRID) forms a multi-state three-helix bundle that is clamped in a single conformation upon complex formation with the Nab3 interaction domain of Nrd1 (NAID). The latter domain forms two long helices that wrap around NRID, resulting in an extensive protein–protein interface that would explain the highly favorable free energy of heterodimerization. Mutagenesis of some conserved hydrophobic residues involved in the heterodimerization leads to temperature-sensitive phenotypes, revealing the importance of this interaction in yeast cell fitness. The Nrd1–Nab3 structure resembles the previously reported Rna14/Rna15 heterodimer structure, which is part of the poly(A)-dependent termination pathway, suggesting that both machineries use similar structural solutions despite they share little sequence homology and are potentially evolutionary divergent. ER -