Fig. 3
HAn formation breaks HINT1-MITF interactions in solution. a A model of (HINT1-Ap4A)n polymer, denoted as HAn, is built based on the HINT1-Ap4A tetramer observed in the crystal structure (circled with a black line). b Interface for MITF (labeled as yellow) overlaps with Ap4A-induced tetramer interface (circled with a black line). Posttranslational modification sites of HINT1 (yellow) is located at the tetramer interface of HINT1. Among them, Lys21 and Tyr109 were reported to directly bind MITF, and modification on these sites disrupted MITF-HINT1 interaction and released MITF transcription activity. c Fluorescence anisotropy assay designed to monitor the interaction between HINT1WT and 5IAF-MITF. Error bars represent the SD of three experimental repeats. Source data are provided as a Source Data file. d Titration of Ap4A and ATP into the 5IAF-MITF-HINT1WT complex at the platform of c. Error bars represent the SD of three experimental repeats. **P < 0.01, from two-tailed Student’s t-test. Source data are provided as a Source Data file. e ATP could not induce HINT1 polymerization and could not release 5IAF-MITF to decrease the fluorescence anisotropy. f Ap4A was able to induce HINT1 polymerization and release 5IAF-MITF to decrease the fluorescence anisotropy
