TABLE 1.
Comparison of in vitro and in silico CK2 phosphorylation site predictions
The number of in vitro CK2 phosphorylation sites in each initiation factor substrate was estimated by the incorporation of [32P] into polypeptide as described under “Experimental Procedures.” Results obtained in vitro are expressed as the average of three experiments ± S.D.
| Factor | No. of CK2 phosphorylation sites |
||||||
|---|---|---|---|---|---|---|---|
| In vitro |
In silico predictions |
||||||
| Scansitea | NetPhosKb | KinasePhosc | |||||
| rWheIF2α | 1.0 ± 0.1 | 1 | 4 | 3 | 4 | 1 | 2 |
| rAteIF2α | 1.8 ± 0.2 | 3 | 5 | 4 | 6 | 1 | 5 |
| rWheIF2β | 0.8 ± 0.1 | 1 | 2 | 0 | 2 | 1 | 1 |
| rAteIF2β | 0.9 ± 0.1 | 0 | 2 | 1 | 1 | 1 | 2 |
| rWheIF3c | 7.4 ± 0.6 | 8 | 15 | 8 | 11 | 5 | 15 |
| rAteIF3c | NDd | 7 | 12 | 8 | 9 | 2 | 8 |
| rWheIF4B | 1.8 ± 0.1 | 2 | 5 | 2 | 3 | 2 | 7 |
| rAteIF4B1 | 5.8 ± 0.1 | 0 | 6 | 4 | 5 | 0 | 5 |
| rAteIF4B2 | 5.8 ± 0.5 | 0 | 9 | 2 | 3 | 1 | 12 |
| rWheIF5 | 3.1 ± 0.1 | 0 | 3 | 1 | 3 | 1 | 3 |
| rAteIF5 | 3.2 ± 0.2 | 0 | 4 | 4 | 6 | 4 | 6 |
| rWhHD2B | ND | 12 | 13 | 12 | 12 | 7 | 14 |
| rAtHD2B | 5.8 ± 0.4 | 9 | 11 | 7 | 7 | 4 | 9 |
| <0.5e | <0.59e | >0.60e | >0.57e | 100%e | 95%e | ||
a ScanSite version 2.0 is available on line.
b NetPhosK version 1.0 is available on line.
c KinasePhos is available on line.
d ND means not determined.
e Phosphorylation sites were predicted using two cutoff values for each program.