Figure 3.
Acid specificity and threshold pH for PKD1L3–PKD2L1 channel activation. (A) Current-density distribution on application of various acids, including HCl, H2SO4, citric acid (CA), malic acid (MA), phosphoric acid (PA), succinic acid (SA) and tartaric acid (TA). The pH of all the acids, except SA (pH 2.6), was adjusted to 2.5. The acidic and neutral solution compositions are described in the supplementary information online. Cells expressing PKD1L3–PKD2L1 channels were exposed to acid solutions at pH 2.5 for 5 s. (B) Average current densities induced by various acid solutions. Error bars and the values in parentheses indicate the s.e.m. and number of cells, respectively. (C) Current-density distribution induced by acids at various pH values. Cells expressing PKD1L3–PKD2L1 channels were exposed to acids at various pH values (2.5, 2.75, 3.0, 3.5 or 4.0) for 5 s each (inset). (D) Average current densities induced by the acid solutions at various pH values. Error bars and values in parentheses indicate the s.e.m. and number of cells, respectively.