Fig. 4.

Composition of TM1 changes the kinetics of desensitization of lamprey ASIC1. A: lamprey ASIC1 currents remain stable under prolonged exposure to protons and are not sensitive to the preconditioning pH. B: the substitution W64R in TM1 makes channels desensitize rapidly in the presence of external protons. C: concentration dependence of activation and steady-state desensitization by protons of ASIC1-W64R. Each data point is the mean ± SD of ≥8 cells. D, top: the amino acid sequence comparison of rat and lamprey TM1. In gray are shown different residues. In the schematic representation of rat-lamprey chimeras of TM1, gray represents rat sequences and black represents lamprey sequences. The number on the left is the residue of the crossover. E: Western blot of surface expression of chimeras using FLAG-monoclonal. Fifteen oocytes for each channel construct (CH) examined by TEVC in D were loaded on the gel. F: time course of representative current traces of chimeras activated by pH 6.5.