Figure 4.

IDR5^del-mediated currents are not modulated by PKA.A, topological representation of PIEZO2 with its major domains, its intracellular intrinsically disordered regions (IDR1–7), and the location of the predicted PKA phosphorylation sites (black and gray circles). B, representative example traces of whole-cell current evoked by increasing mechanical indentation from PIEZO2 (left) and the previously characterized IDR5^del PIEZO2 mutant (right) in the presence of the PKA inhibitor KT5720 or the PKA activator 8-bromo-cAMP. C, displacement–response curves of peak current amplitudes of PIEZO2 and the indicated IDR^del mutants after inhibition and activation of PKA. Data are presented as the mean ± SD. Number of cells per group is indicated in the legend. Comparison with Mann–Whitney test, p < 0.05∗, p < 0.001∗∗, p < 0.0001∗∗∗ 8-Br-cAMP versus KT. D and E, inactivation time constant (τ_inact) (D) and mechanical activation thresholds (E) of whole-cell current from PIEZO2 and IDR^del mutants treated with KT5720 (filled bars) or 8-Br-cAMP (dashed bars). Data are presented as the mean ± SD with individual values. Number of cells per group are identical to those in (C). Inactivation time constants and activation thresholds of KT5720- and 8-Br-cAMP-treated cells were compared pairwise for each mutant using Mann–Whitney test. τ_inact: PIEZO2, p = 0.000081; IDR1^delp = 0.0020. Activation threshold: PIEZO2, p = 0.004; IDR3^delp = 0.0018; IDR6^delp = 0.012. 8-Br-cAMP, 8-bromo-cyclic-AMP.