Figure 2. Protein–protein interaction matrix of the cytosolic maturation machinery of the 60S large ribosomal subunit from Saccharomyces cerevisiae. Each dark gray box within the matrix indicates a physical interaction between the cytosolic maturation factors. Interactions were retrieved and consolidated from BioGRID (Version 3.2.106). The protein names, corresponding gene codes, and the total number of physically interacting proteins are listed in the first 3 rows. The rows and columns are symmetrically ordered according to the sequence of the proteins acting within the main path of the model followed by the proteins relevant for stalk assembly, namely RPP0, Mrt4, and Yvh1. The interactions of the Rei1 protein are highlighted by a framed column. The light gray underlay accentuates the direct mechanistic interaction partners of Rei1, also refer to (Fig. 1).