Amyloid-β protein aggregation-regulating factors

1. A polypeptide which (a) suppresses or promotes the aggregation of

amyloid-β or (b) which is an immunogenic polypeptide, and which is encoded by an isolated polynucleotide selected from the group consisting of:

(a) a polynucleotide that comprises a polynucleotide sequence as set forth in SEQ ID NO: 3, 5, 7 or 9,

(b) a polynucleotide that encodes a polypeptide having an amino acid sequence as set forth in SEQ ID NO: 4, 6, 8 or 10,

(c) a polynucleotide that hybridizes under stringent conditions to a polynucleotide comprising a polynucleotide sequence as set forth in SEQ ID NO: 3, 5, 7 or 9, wherein the stringent conditions comprise washing in 0.1×SSC and 0.1% SDS at 65° C.,

(d) a polynucleotide that shows at least 95% homology to a polynucleotide sequence as set forth in SEQ ID NO: 3, 5, 7 or 9, and

(e) a fragment of the polynucleotide of (a), (b), (c) or (d).

2. The polypeptide of claim 1 , which suppresses the aggregation of amyloid-β protein.

3. The polypeptide of claim 1 , which promotes the aggregation of amyloid-β protein.

4. The polypeptide of claim 1 which is immunogenic.

5. The polypeptide of claim 1 which is encoded by a polynucleotide sequence as set forth in SEQ ID NO: 3, 5, 7 or 9.

6. The polypeptide of claim 1 which comprises an amino acid sequence as set forth in SEQ ID NO: 4, 6, 8 or 10.

7. The polypeptide of claim 1 which is encoded by a polynucleotide that hybridizes under stringent conditions to a polynucleotide comprising a nucleotide sequence as set forth in SEQ ID NO: 3, 5, 7 or 9, wherein the stringent conditions comprise washing in 0.1×SSC and 0.1% SDS at 65° C.

8. The polypeptide of claim 1 which is encoded by a polynucleotide which shows at least 95% homology to a polynucleotide sequence as set forth in SEQ ID NO: 3, 5, 7 or 9.

9. The polypeptide of claim 1 which is encoded by a fragment of SEQ ID NO: 3, 5, 7 or 9.

10. A composition comprising the polypeptide of claim 1 and a pharmaceutically acceptable carrier or vehicle.

11. The composition of claim 10 , wherein said polypeptide is encoded by a polynucleotide comprising SEQ ID NOS: 3 or 7 and inhibits amyloid-β-protein aggregation.

12. The composition of claim 10 , wherein said polypeptide is encoded by a polynucleotide comprising SEQ ID NOS: 5 or 9 and which enhances amyloid-β-protein aggregation.

13. A method for inhibiting amyloid-β aggregation comprising contacting a sample containing amyloid-β with the polypeptide of claim 1 .

14. A method for enhancing amyloid-β aggregation comprising contacting a sample containing amyloid-β with the polypeptide of claim 1 .

15. A method for treating Alzheimer's Disease comprising administering to a subject in need thereof a polypeptide of claim 1 which inhibits amyloid-β aggregation.

16. A method for producing an antibody that binds to the polypeptide of claim 1 , comprising immunizing an animal with the polypeptide of claim 1 .

17. An immunological assay comprising:

contacting the polypeptide of claim 1 with a sample containing an antibody, and

monitoring the binding of antibody in said sample with the polypeptide of claim 1 ,

wherein binding of antibodies in said sample to said polypeptide is indicative of the presence of antibodies that immunologically react with the polypeptide of claim 18 or inhibit its ability to suppress or promote the aggregation or deposition of amyloid β protein.

18. A method of screening for a compound that regulates the activity of the polypeptide of claim 1 , wherein said method comprises:

(a) contacting a candidate compound with said polypeptide, or with a cell expressing said polypeptide, in the presence of amyloid-β protein,

(b) detecting the aggregation or deposition of amyloid-β protein, and

(c) selecting a candidate compound that regulates the aggregation or deposition of amyloid-β protein.