Polynucleotides encoding a human 3-phosphoinositide- dependent protein kinase

1. An isolated polynucleotide encoding a human 3-phosphoinositide-dependent protein kinase that phosphorylates and activates protein kinase Bα at a rate substantially the same as the rate wild-type PDK1 activates protein kinase Bα, wherein the protein kinase comprises amino acids 83 to 342 and 450-550 of SEQ ID NO: 1.

2. The polynucleotide according to claim 1 , wherein the 3-phosphoinositide-dependent protein kinase has a molecular weight of about 67 kDa as determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis.

3. An isolated polynucleotide encoding a 3-phosphoinositide-dependent protein kinase having the amino acid sequence as shown in SEQ ID NO: 1 except for 1 to 4 conservative substitutions therein and wherein the protein kinase activates protein kinase Bα at a rate substantially the same as the rate wild-type PDK1 activates protein kinase Bα.

4. The polynucleotide according to claim 1 , wherein the 3-phosphoinositide-dependent protein kinase is a phosphatidylinositol-3,4,5-triphosphate-dependent protein kinase.

5. The polynucleotide according to claim 1 , wherein the 3-phosphoinositide-dependent protein kinase activates protein kinase Bα in the presence of the D-enantiomer of sn-1-stearoyl-2-arachidonyl phosphatidylinositol 3,4,5-trisphosphate but does not activate protein kinase Bα in the presence of the L-enantiomer of the said phosphatidylinositol 3,4, 5-trisphosphate.

6. The polynucleotide according to claim 1 , wherein the 3-phosphoinositide-dependent protein kinase is activated by the D-enantiomer of sn-1,2-dipalmitoyl phosphatidylinositol 3,4,5-trisphosphate or sn-1,2-dipalmitoyl phosphatidylinositol 3,4-bisphosphate but is not activated by the L-enantiomers of the said phosphatidyl inositol phosphates.

7. The polynucleotide according to claim 1 , wherein the 3-phosphoinositide-dependent protein kinase is not activated by phosphatidylinositol 3,5-bisphosphate or phosphatidylinositol 4,5-bisphosphate or phosphatidylinositol 4-phosphate or phosphatidylinositol 3-phosphate or inositol 1,3,4,5-tetrakisphosphate.

8. The polynucleotide according to claim 1 which contains no introns.

9. A vector comprising the polynucleotide according to claim 1 .

10. An isolated host cell comprising the polynucleotide according to claim 1 .

11. An isolated host cell comprising the vector according to claim 9 .

12. A method of making a 3-phosphoinositide-dependent protein kinase that phosphorylates and activates Bα or a fusion protein of said 3-phosphoinositide-dependent protein kinase, the method comprising culturing the host cell according to claim 10 which expresses said 3-phosphoinositide-dependent protein kinase and isolating said 3-phosphoinositide-dependent protein kinase from said host culture.

13. The polynucleotide according to claim 1 encoding a fusion protein comprising said 3-phosphoinositide-dependent protein kinase.

14. The polynucleotide according to claim 1 , wherein the protein kinase comprises amino acids 52-556 of SEQ ID NO: 1 or amino acids 52-556 of SEQ ID NO: 1 except for 1 to 4 conservative substitutions therein.

15. The polynucleotide according to claim 14 encoding a fusion protein comprising said 3-phosphoinositide-dependent protein kinase.