Interaction of NMDA receptor with protein tyrosine phosphatase

• US 20030092071A1
• Filed: 09/18/2002
• Published: 05/15/2003
• Est. Priority Date: 02/01/2000
• Status: Abandoned Application

• Current Assignee: AGY Therapeutics, Inc.
• Original Assignee: AGY Therapeutics, Inc.
• Inventors: Liu, Jenkuei, Jerecic, Jasna, Melcher, Thorsten, Braithwaite, Steven, Kask, Kalev
• Application Number:
  US10/246,837
• Publication Number:
  US 20030092071A1
• Time in Patent Office: Days
• US Class Current: 435/7.2
• CPC Class Codes: C12Q 1/42 involving phosphatase
• CPC Class Codes: G01N 2500/00 Screening for compounds of potential therapeutic value
• CPC Class Codes: G01N 33/9406 Neurotransmitters

Abstract

The present invention relates to the identification of a binding between NMDA receptor (NMDA-R) subunits and a protein tyrosine phosphatase (PTP), e.g., PTPL1. The present invention provides methods for screening a PTP agonist or antagonist that modulates NMDA-R signaling. The present invention also provides methods and compositions for treatment of disorders mediated by abnormal NMDA-R signaling. The present invention further provides methods for isolating PTPL1 from a biological preparation.

Claims

1. A method for identifying a modulator of N-methyl-D-aspartate receptor (NMDA-R) signaling activity, comprising detecting the ability of an agent to modulate the phosphatase activity of a protein tyrosine phosphatase L1 (PTPL1) on a substrate or to modulate the binding of the PTP to NMDA-R, thereby identifying the modulator, wherein the PTPL1 is capable of directly or indirectly dephosphorylating NMDA-R.

2. The method according to claim 1, wherein said PTPL1 is capable of dephosphorylating a protein tyrosine kinase (PTK), which PTK phosphorylates NMDA-R.

3. The method according to claim 2, wherein said PTK is Src.

4. The method of claim 1, wherein the PTPL1 is human.

5. The method of claim 1, wherein the modulator is identified by detecting its ability to modulate the phosphatase activity of the PTPL1.

6. The method of claim 1, wherein the modulator is identified by detecting its ability to modulate the binding of the PTP to the NMDA-R.

7. A method for identifying an agent as a modulator of NMDA-R signaling, comprising:

(a) contacting

(i) the agent

(ii) PTPL1 and a protein tyrosine kinase (PTK) that phosphorylates NMDA-R; and

(iii) NMDA-R or a subunit thereof;

wherein either or both of (ii) and (iii) is substantially pure or recombinantly expressed;

(b) measuring the tyrosine phosphorylation level of the NMDA-R or subunit;

(c) comparing the NMDA-R tyrosine phosphorylation level in the presence of the agent with the NMDA-R tyrosine phosphorylation level in the absence of the agent,

wherein a difference in tyrosine phosphorylation levels identifies the agent as a modulator of NMDA-R signaling.

8. The method of claim 7, wherein said NMDA-R and said PTPL1 exist in a PTPL1/NMDA-R-containing protein complex.

9. The method of claim 7, wherein said agent enhances the ability of PTPL1 to dephosphorylate said PTK.

10. The method of claim 7, wherein said agent inhibits the ability of PTPL1 to dephosphorylate said PTK.

11. The method of claim 7, wherein said agent modulates binding of PTPL1 to NMDA-R.

12. The method of claim 11, wherein said agent promotes or enhances binding of PTPL1 to NMDA-R.

13. The method of claim 11, wherein said agent disrupts or inhibits binding of PTPL1 to NMDA-R.

14. A method for identifying a nucleic acid molecule that modulates NMDA-R signaling, comprising:

(a) obtaining a cell culture coexpressing the NMDA-R and PTPL1

(b) introducing a nucleic acid molecule encoding a gene product into a portion of the cells;

thereby producing cells comprising the nucleic acid molecule;

(c) culturing the cells in (b) under conditions in which the gene product is expressed;

(d) measuring the tyrosine phosphorylation level of NMDA-R in the cells in (c) and comparing the level with that of control cells into which the nucleic acid molecule has not been introduced

wherein a difference in tyrosine phosphorylation levels identifies the nucleic acid molecule as a modulator of NMDA-R signaling.

15. A method for treating a disease mediated by abnormal NMDA-R-signaling, comprising administering a modulator of a PTPL1 activity, thereby modulating the level of tyrosine phosphorylation of NMDA-R.

16. The method of claim 15, wherein the modulator modulates the ability of PTPL1 to directly or indirectly dephosphorylate NMDA-R.

17. The method of claim 15, wherein the modulator modulates the ability of PTPL1 to bind to NMDA-R.

18. The method of claim 15, wherein the modulator is a PTPL1 agonist, wherein the disease is selected from the group consisting of (i) ischemic stroke;

(ii) head trauma or brain injury;

(iii) Huntington'"'"'s disease;

(iv) spinocerebellar degeneration;

(v) motor neuron diseases;

(vi) epilepsy;

(vii) neuropathic pain;

(viii) chronic pain; and

(ix) alcohol tolerance.

19. The method of claim 15, wherein the modulator is a PTPL1 antagonist, wherein the disease is selected from the group consisting of (i) schizophrenia;

(ii) Alzheimer disease;

(iii) dementia;

(iv) psychosis;

(v) drug addiction; and

(vi) ethanol sensitivity.

20. The method of claim 15, wherein the modulator is a PTPL1 antagonist and affects the ability of a protein tyrosine kinase to phosphorylate NMDA-R.