Nucleic acid encoding proteins involved in protein degradation, products and methods related thereto
In accordance with the present invention, there are provided novel Siah-Mediated-Degradation-Proteins (SMDPS) and/or SCF-Complex Proteins (SCPs). Nucleic acid sequences encoding such proteins and assays employing same are also disclosed. The invention SMDPs and/or SCPs can be employed in a variety of ways, for example, for the production of anti-SMDP and/or SCP antibodies thereto, in therapeutic compositions, and methods employing such proteins and/or antibodies for drug screening, functional genomics and other applications. Also provided are transgenic non-human mammals that express the invention protein. Also provided are compositions and methods for targeting the destruction of selected polypeptides in eukaryotic cells based on the ubiquitin-independent mechanism by which ornithine decarboxylase is degraded by the 26S proteasome.
1. An isolated chimeric protein that comprises:
a target-protein binding domain operatively linked to a protein-degradation binding domain of ornithine decarboxylase, and
a flexible linker sequence [Gly-Gly-Gly-Gly-Ser] 3 (SEQ ID NO: 61) between the target-protein binding domain and the protein-degradation binding domain of ornithine decarboxylase,
wherein binding of the target-protein binding domain of the chimeric protein to a target protein in a cell induces degradation of the target protein in the cell.
2. The isolated chimeric protein of claim 1 , wherein the protein-degradation binding domain of ornithine decarboxylase is an ornithine decarboxylase C-terminal region polypeptide.
3. The isolated chimeric protein of claim 1 , comprising a protein-degradation binding domain of human ornithine decarboxylase.
4. The isolated chimeric protein of claim 1 , wherein the protein-degradation binding domain of ornithine decarboxylase is a human ornithine decarboxylase C-terminal region polypeptide.
5. The isolated chimeric protein of claim 1 , comprising, in order from N-terminus to C-terminus, (a) the target-protein binding domain, (b) the flexible linker sequence, and (c) the protein-degradation binding domain of ornithine decarboxylase.
6. The isolated chimeric protein of claim 1 , further comprising an epitope tag sequence.
7. A pharmaceutical composition comprising a therapeutically effective amount of the chimeric protein of claim 1 , and a pharmaceutically acceptable carrier.
8. The pharmaceutical composition of claim 7 , further comprising a polyamine.