Phosphorylation of Tyr sites of USP1 protein in K562 cell as a progression factor of chronic myeloid leukemia

Abstract

Aim. To study the properties of Tyr phosphorylation of USP1 protein in K562 cells. Methods. The bioinformatics analysis of the USP1 protein sites of phosphorylayion using the Phosphosite software. Coimmunoprecipitation, Western blot. Immunofluorescence analysis and confocal microscopy. Results. Potential phosphorylation sites for USP1 protein for Tyr are provided. Phosphorylated form of USP1 protein detected in K562 cells. Using immunofluorescence analysis and confocal microscopy, we found that Tyr phosphorylated forms of USP1 protein are localized in the nucleus. Conclusions. We deem that Tyr phosphorylation of USP1 protein is the consequence of its interaction with Bcr-Abl oncoprotein, which has high kinase activity. USP1 phosphorylation can raise deubiquitinating activity of this protein, and as a result, avert the proteosomal degradation of Bcr-Abl in cell and facilitate the progress of the disease.Keywords: chronic myeloid leukemia, Bcr-Abl, USP1, Tyr site of phosphorylation.