NIP30Regulates REGγ's Function And Its Mechanisms

The proteasome activator REGy has been demonstrated to mediate a shortcut to destruction of intact mammalian proteins, such as SRC-3, p21. Lately, it has been figured out how REGy play its role in the initiation and development of the cancer by inhibiting the biological activity of p53.Yet the biological roles of REGy and the underlying mechanism are not fully understood. Here, for the first time,we found a novel protein NIP30can interact with REGy by Yeast Two-Hybrid Assay. Our evidence in celluar assay showed that NIP30can upregulate p21protein level by inhibiting its degradation through REGy-dependent proteasome degradation pathway, vice versa. The upregulation of p21protein level through NIP30depends on the interaction between NIP30and REGy. Further more, we found that the interaction between NIP30and REGy is regulated through the serine phosphorlyation of NIP30at amino acids226to230. That is to say, when NIP30is phosphorlyated at amino acids226to230, NIP30interacts with REGy, which can inhibit the degradation of p21by REGy.