“…Our findings identify pH-regulated transcription factor-DNA binding selectivity with relevance to how pHi dynamics can regulate gene expression for myriad cell behaviours.15 , diabetes 16,17 , and neurodegeneration 18,19 . The molecular mechanisms by which pHi dynamics regulates normal and pathological cell behaviours is often mediated by protein electrostatics and the protonation state of key residues in endogenous pH sensitive proteins termed "pH sensors" 20,21 .Of all amino acids that undergo protonation state changes in solution, histidine side chains exhibit the closest pKa (6.5) to physiological pH. However, the pKa of histidine, aspartic acid, glutamic acid, and buried lysine can be upshifted or downshifted depending on the protein electrostatics environment to enable titration within the cellular pH range of 7.0-7.8 6,22,23 .Changes in the protonation state of key amino acids in response to small changes in pH (0.2-0.3) can significantly alter protein structure and function, including activity 7,24-26 and ligand binding 5,6,[27][28][29] as well as stability 30-32 and aggregation 33,34 .…”