FIGURE 11.

Model of Grc3/Las1 molecular crosstalk. Grc3/Las1 assembles into a super dimer driven by homodimerization of the Las1 nuclease domain and Grc3 PNK domain (Pillon et al. 2017). Each Grc3 PNK domain encodes four motifs, including the P-loop (red), Walker B (blue), Clasp (purple), and Lid (orange), important for kinase activity, nuclease activity, and cell viability. Approximate positions of the motifs relative to one another are based upon the homology model from Figure 4C. PNK residues identified to be critical for molecular crosstalk are encircled (Grc3 D283 and L361). Yellow asterisks highlight the Grc3 C-terminal tail and the Las1 HEPN active site, which were previously established to also mediate molecular crosstalk (Pillon et al. 2017). The X marks residues that are dispensable, whereas the checkmark identifies critical residues.