Inhibition of USP1, a new partner of Bcr-Abl, results in decrease of Bcr-Abl level in K562 cells.

AIM

To analyze interaction of ubiquitin specific peptidase 1 (USP1) with Bcr-Abl and to assess the relation between USP1 functional activity and Bcr-Abl expression in K562 chronic myeloid leukemia cells.

MATERIALS AND METHODS

The interaction between USP1 and Bcr-Abl in K562 cells was analyzed by co-immunoprecipitation, Western blot analysis, and confocal microscopy.

RESULTS

A direct interaction between Bcr-Abl oncoprotein and USP1 protein in K562 cells was established by co-immunoprecipitation. Immunofluorescence analysis and confocal microscopy revealed that Bcr-Abl/USP1 protein complex is formed in the cell nucleus. The inhibition of USP1 protein activity by ML323 reduced the level of Bcr-Abl oncoprotein in K562 cells.

CONCLUSIONS

USP1 protein has been identified as a new protein partner of Bcr-Abl oncoprotein in chronic myeloid leukemia. The relationship between the functional activity of USP1 protein and the level of Bcr-Abl oncoprotein has been demonstrated, suggesting that the targeted inhibition of USP1 activity could be a challenging approach for reducing Bcr-Abl expression.