Compositions and methods for modulating rank activities
The present invention provides methods for identifying agents capable of modulating RANK-mediated signaling pathways. The present invention also provides compositions and methods of using the same to treat osteoporosis or other RANK-related diseases. The present invention is based on the functional and structural analysis of three TRAF-binding motifs (PTM)—namely, PTM3, PTM5, and PTM6, each of which has been found to play a distinct role in the activation of RANK-mediated intracellular signaling. These PTMs can be used to screen for RANK modulators. These PTMs also represent potential drug targets for diseases that are associated with abnormal RANK expression or activity.
1. An isolated molecule of interest that modulates a RANK-mediated signaling pathway through one or more TNF receptor associated factors (TRAF) binding motif (“PTM motif”), wherein said isolated molecule of interest comprises a PTM3 motif having an amino acid sequence PFSEP (SEQ ID NO:4) or PFQEP (SEQ ID NO: 1), a PTM5 motif having an amino acid sequence PVQEET (SEQ ID NO:2), and a PTM6 motif having an amino acid sequence PVQEQG (SEQ ID NO:3).
2. The isolated molecule of interest of claim 1 , wherein said isolated molecule of interest comprises a PTM3 motif having an amino acid sequence PFSEP (SEQ ID NO:4), a PTM5 motif having an amino acid sequence PVQEET (SEQ ID NO:2), and a PTM6 motif having an amino acid sequence PVQEQG (SEQ ID NO:3).
3. The isolated molecule of interest of claim 1 , wherein said isolated molecule of interest comprises a PTM3 motif having an amino acid sequence PFQEP (SEQ ID NO: 1), a PTM5 motif having an amino acid sequence PVQEET (SEQ ID NO:2), and a PTM6 motif having an amino acid sequence PVQEQG (SEQ ID NO:3).
4. A composition comprising a molecule of interest of claim 1 , wherein said composition is capable of modulating a PTM3-mediated RANK signaling pathway.
5. composition comprising a molecule of interest of claim 1 , wherein said composition is capable of modulating a PTM5-mediated RANK signaling pathway.
6. A composition comprising a molecule of interest of claim 1 , wherein said composition is capable of modulating a PTM6-mediated RANK signaling pathway.
7. A composition comprising one or more molecule of claim 1 , wherein said molecule modulates at least two RANK-mediated pathways selected from a PTM3-mediated RANK signaling pathway, a PTM5-mediated RANK signaling pathway, and a PTM6-mediated RANK signaling pathway.
8. An isolated chimeric transmembrane protein comprising an extracellular domain of a non-RANK TNFR superfamily member selected from the group consisting of TNFR1, TNFR2, Fas, and CD40 and a RANK intracellular domain comprising one or more PTM motifs, wherein said PTM motif is PTM3 motif having an amino acid sequence PFSEP (SEQ ID NO:4) or PFQEP (SEQ ID NO:1), PTM5 motif having an amino acid sequence PVQEET (SEQ ID NO:2), or PTM6 motif having an amino acid sequence PVQEQG (SEQ ID NO:3).
9. The chimeric transmembrane protein of claim 8 , wherein said RANK intracellular domain comprises PTM3 motif having an amino acid sequence PFSEP (SEQ ID NO:4) or PFQEP (SEQ ID NO:1).
10. The chimeric transmembrane protein of claim 8 , wherein said RANK intracellular domain comprises PTM5 motif having an amino acid sequence PVQEET (SEQ ID NO:2).
11. The chimeric transmembrane protein of claim 8 , wherein said RANK intracellular domain comprises PTM6 motif having an amino acid sequence PVQEQG (SEQ ID NO:3).
12. The chimeric transmembrane protein of claim 9 , wherein said RANK intracellular domain comprises PTM3 motif having an amino acid sequence PFSEP (SEQ ID NO:4) or PFQEP (SEQ ID NO: 1) but not PTM5 or PTM6 motif, or both.
13. The chimeric transmembrane protein of claim 10 , wherein said RANK intracellular domain comprises PTM5 motif having an amino acid sequence PVQEET (SEQ ID NO:2) but not PTM3 or PTM6 motif, or both.
14. The chimeric transmembrane protein of claim 11 , wherein said RANK intracellular domain comprises PTM6 motif having an amino acid sequence PVQEQG (SEQ ID NO:3) but not PTM3 or PTM5 motif, or both.