FIG 1.

Asp1 kinase generates IP₈. (A to C) HPLC elution profiles of inositol polyphosphates of wild-type (WT), asp1^D333A, and asp1Δ strains. S. pombe cells were radiolabeled with [³H]inositol, and cell lysates were separated using anion-exchange HPLC. CPM, counts per minute. (D) Diagrammatic representations of IP₈ levels relative to those of IP₆ and IP₇ levels relative to those of IP₆ (WT, n = 3; asp1^D333A strain, n = 2; asp1Δ strain, n = 3; ***, P ≤ 0.001; *, P ≤ 0.05, t test). The fold change of IP₈/IP₆ is as follows (WT set at 1.00): 0.12 for the asp1^D333A strain and 0.11 for the asp1Δ strain. Fold changes of IP₇/IP₆ are as follows: 6.26 for the asp1^D333A strain and 4.56 for the asp1Δ strain. n, number of experiments done.