Study On The Stability Of Schizosaccharomyces Pombe Protein Mrz1

The mitochondrial outer membrane mediates numerous interactions between the mitochondrial metabolic and genetic systems and the rest of the eukaryotic cell,thus,the outer membrane protein plays a crucial role in the biogenesis,inheritance and morphology of the organelle.A large-scale localization study found that the Schizosaccharomyces pombe protein Mrz1 is located in the mitochondria and the nucleus.Further research found that Mrz1 is located on the outer mitochondrial membrane and nucleus,and its RING finger domain is related to the ubiquitin proteasome system(UPS),but the protein function is unknown.In this paper,Western Blot technology detected that the protein expression level of Mrz1 which is decreased in the late stage of cell growth,and q RT-PCR technology detected that the transcriptional expression of mrz1 was relatively stable in the whole growth phase of the cell.It is speculated that the stability of Mrz1 may be related to post-translational modification.The UPS is the principal means by which cells regulate their proteome.Treatment of cells with proteasome inhibitor MG132 caused accumulation of ubiquitinated protein in the cells.After treatment of yeast cells with proteasome inhibitor MG132,it was found that the protein expression of Mrz1 increased in the later period.Therefore,it is believed that UPS may be involved in the regulation of protein Mrz1 degradation expression.We want to understand how Mrz1 is ubiquitinated.To this end,we get 10 non-essential E2 ubiquitin-binding enzyme gene knockout strains in Schizosaccharomyces pombe and then Western Blot technology was used to detect the expression level of Mrz1 protein in the 10 knockout strains.It was found that only when the gene ubc13 was deleted,the protein expression level of Mrz1 is partially recovery.It is speculated that Ubc13 is involved in Mrz1 degradation regulation,its absence makes Mrz1 more stable.In addition,in budding yeast,Mms2 forms a complex with Ubc13 to participate in the degradation of ubiquitin,so a doubleknockout strain named ?mms2?ubc13 was constructed.The results showed that the protein expression level of Mrz1 in ?mms2?ubc13 and ?ubc13 were basically the same,indicating that Mms2 did not participate in the further degradation of Mrz1 by Ubc13.This study found that Mrz1 was degraded by ubiquitination at the late stage of cell growth,which laid the foundation for further research on the degradation mechanism of Mrz1 and the function of Mrz1,so as to better improve the study of the possibility mechanism of mitochondrial protein ubiquitination.