Figure 7. Schematic model of pH i... | Rockefeller University Press

Figure 7.

Schematic model of pHi regulation on TMEM16F and TMEM16A under physiological Ca2+i. Under low pHi conditions, protonation of the primary Ca2+ binding residues in the pore can significantly reduce Ca2+ binding affinity of TMEM16 proteins and suppress their activation. In contrast, high pHi deprotonates the Ca2+ binding residues and enhances Ca2+ binding and TMEM16 activation. The size of blue arrows represents the open probability of TMEM16 proteins. The size of Ca2+ ions represents the strength of apparent Ca2+ binding affinity.

Schematic model of pH_i regulation on TMEM16F and TMEM16A under physiological Ca²⁺_i. Under low pH_i conditions, protonation of the primary Ca²⁺ binding residues in the pore can significantly reduce Ca²⁺ binding affinity of TMEM16 proteins and suppress their activation. In contrast, high pH_i deprotonates the Ca²⁺ binding residues and enhances Ca²⁺ binding and TMEM16 activation. The size of blue arrows represents the open probability of TMEM16 proteins. The size of Ca²⁺ ions represents the strength of apparent Ca²⁺ binding affinity.