FIGURE 5.

Chem155A and its equivalent C-terminal peptide are weak antagonists of chem157S by calcium flux assay. A, Fluo-8-labeled cells were pretreated with the indicated molar ratio of chem155A protein (▴), FA peptide (△), and scrambled FA peptide, AFQGPFYFSH (▿), for 10 min and then stimulated with 100 nm 9-mer (C-terminal peptide of chem157S). The data are shown as the fluorescence intensity relative to that in the absence of antagonist (n ≥ 3). B, Fluo-8-labeled cells were pretreated with the indicated molar ratio of chem155A protein (▴) and FA peptide (△) for 10 min and then stimulated with 30 nm chem157S. The curves represent the mean ± S.D. of at least three independent experiments. *, p < 0.01; #, p < 0.05 compared with no antagonist by paired Student's t test; §, p < 0.05 when chem155A is compared with FA peptide by paired Student's t test.