Screening assay for agents that alter target of rapamycin activity

1. A method for measuring the ability of an agent to modulate the ability of isolated native Target of Rapamycin (TOR) protein to phosphorylate a TOR substrate, comprising determining the level of phosphorylation by said isolated native TOR of said TOR substrate under conditions in which said isolated native TOR and the TOR substrate interact:

(a) in the absence of said agent;

(b) in the presence of said agent; and

comparing the level of phosphorylation of said TOR substrate from (a) with the level of phosphorylation from (b), wherein a difference in the level of phosphorylation of said TOR substrate from (a) and the level of phosphorylation from (b) indicates that the agent has the ability to modulate the ability of TOR protein to phosphorylate the TOR substrate,

wherein said isolated native TOR causes the difference in the level of phosphorylation of said TOR substrate from (a) and the level of phosphorylation from (b).

2. The method of claim 1 wherein said TOR naturally occurs in a host cell.

3. The method of claim 2 wherein said host cell is a mammalian cell.

4. The method of claim 3 wherein said host cell is a rat cell.

5. The method of claim 4 wherein said host cell is a brain cell.

6. The method of claim 2 wherein said native TOR is isolated from said host cell.

7. The method of claim 1 wherein said isolated native TOR is isolated from rat brain extract extracted and partially purified from whole rat brain tissue.

8. The method of claim 1 wherein said isolated native TOR is isolated from bovine testes extract extracted and partially purified from bovine testes.

9. The method of claim 1 wherein said TOR substrate is a fusion protein.

10. The method of claim 9 wherein said fusion protein is selected from the group consisting of p70 S6 Kinase-GST and 4E-BPI-GST.

11. The method of claim 10 wherein said fusion protein further comprises a phosphor-acceptor site.

12. The method of claim 11 wherein said fusion protein further comprises the phosphor-acceptor residue threonine 389.

13. The method of claim 11 wherein said detection of phosphorylation is quantitative.

14. The method of claim 13 wherein said detection of phosphorylation is done using two-stage enzyme linked antibodies.

15. The method of claim 14 wherein said antibody detects levels of p70 S6 Kinase only when phosphorylated at threonine 389.

16. The method of claim 1 wherein the ability of an agent to modulate the ability of isolated native TOR to phosphorylate said TOR substrate is measured in a high throughput screening format.

17. The method of claim 1 wherein conditions in which isolated native TOR and the TOR substrate interact comprise the presence of isolated native TOR and the TOR substrate.

18. The method of claim 1 wherein the agent is not rapamycin, wortmannin, or LY29004.

19. The method of claim 1 wherein said isolated native TOR has phosphorylation activity.

20. A method for measuring the ability of an agent to modulate the ability of isolated native Target of Rapamycin (TOR) protein to phosphorylate a TOR substrate, comprising determining the level of phosphorylation by said isolated native TOR of said TOR substrate under conditions in which said isolated native TOR and the TOR substrate interact:

(a) in the absence of said agent;

(b) in the presence of said agent; and

comparing the level of phosphorylation of said TOR substrate from (a) with the level of phosphorylation from (b), wherein a difference in the level of phosphorylation of said TOR substrate from (a) and the level of phosphorylation from (b) indicates that the agent has the ability to modulate the ability of TOR protein to phosphorylate the TOR substrate,

wherein said isolated native TOR is isolated from eukaryotic tissue extract,

wherein conditions in which isolated native TOR and the TOR substrate interact comprise the presence of isolated native TOR and the TOR substrate,

wherein said isolated native TOR naturally occurs in a host cell,

wherein said isolated native TOR is isolated from eukaryotic tissue extract extracted and partially purified from said host cell,

wherein said isolated native TOR has phosphorylation activity.

21. The method of claim 1 wherein said isolated native TOR is isolated from eukaryotic tissue extract extracted and partially purified from eukaryotic tissue.

22. The method of claim 1 wherein said isolated native TOR is isolated from mammalian tissue extract extracted and partially purified from mammalian tissue.

23. The method of claim 1 wherein said isolated native TOR is isolated from rat brain extract.

24. The method of claim 1 wherein said isolated native TOR is a TOR elution fraction.

25. The method of claim 1 , wherein said isolated native TOR is isolated by a method comprising the steps of:

(i) homogenizing eukaryotic tissue in an extraction buffer into supernate and soluble material;

(ii) removing supernate from soluble material;

(iii) dialyzing the soluble material; and

(iv) performing affinity chromatography on the soluble material after dialysis.

26. The method of claim 25 wherein the eukaryotic tissue is mammalian tissue.

27. The method of claim 26 wherein the mammalian tissue is rat brain tissue.

28. A method for measuring the ability of an agent to modulate the ability of isolated native Target of Rapamycin (TOR) protein to phosphorylate a TOR substrate, comprising determining the level of phosphorylation by said isolated native TOR of said TOR substrate under conditions in which said isolated native TOR and the TOR substrate interact:

(a) in the absence of said agent;

(b) in the presence of said agent; and

comparing the level of phosphorylation of said TOR substrate from (a) with the level of phosphorylation from (b), wherein a difference in the level of phosphorylation of said TOR substrate from (a) and the level of phosphorylation from (b) indicates that the agent has the ability to modulate the ability of TOR protein to phosphorylate the TOR substrate,

wherein said isolated native TOR is isolated from eukaryotic tissue extract.