NMMHC-IIA-dependent nuclear location of CXCR4 promotes migration and invasion in renal cell carcinoma.

The chemokine receptor cysteine (C)-X-C receptor (CXCR4) is a G-protein-coupled receptor that exerts a vital role in distant metastasis of renal cell carcinoma (RCC). Emerging evidence demonstrates that CXCR4 as the cytomembrane receptor translocated into the nucleus to facilitate cell migration and, therefore, determine the prognosis of several types of malignancies. However, the biological mechanism of nuclear location of CXCR4 remains unclear. In the present study, we confirmed the significant implications of the putative nuclear localization sequence (NLS) '146RPRK149̓ on CXCR4 subcellular localization and metastatic potential by point-mutation assay in RCC cell lines. Importantly, mass spectrum followed by immunoprecipitation identified non-muscle myosin heavy chain-IIA (NMMHC-IIA) as the CXCR4-interacting protein. Furthermore, pharmaceutical inhibition of NMMHC-IIA by blebbistatin dampened the nuclear translocation of CXCR4 as well as the metastatic capacity of RCC cells. In conclusion, the present study may drive the comprehensive progress toward elucidating the mechanism responsible for CXCR4 nuclear function and metastasis in tumors.