Table 1.
Relative Activities of Arabidopsis PI4P 5-Kinase Isoforms Expressed in Roots
| Substrate | PtdIns4P/PtdIns3P | |||
|---|---|---|---|---|
| Protein | PtdIns3P | PtdIns4P | PtdIns5P | Activity Ratio |
| MBP | 2 ± 0.3 | 4 ± 0 | – | – |
| PIP5K1 | 5 ± 0.8 | 205 ± 17 | – | 41.0 |
| PIP5K2 | 52 ± 8 | 1206 ± 156 | – | 23.0 |
| PIP5K3 | 178 ± 27 | 1972 ± 66 | – | 11.0 |
| PIP5K7 | 2 ± 0.3 | 37 ± 6 | – | 18.5 |
| PIP5K8 | 3 ± 0.5 | 27 ± 3 | – | 9.0 |
| PIP5K9 | 4 ± 0.6 | 142 ± 23 | – | 35.5 |
Catalytic activities were tested in vitro against different phosphatidylinositol-monophosphate substrates and indicate the rate of product formation in fmol min−1. Recombinant protein concentrations were balanced according to protein gel blot analysis. Data are the means of two independent experiments ± sd.