Phosphorylation of myofibrillogenesis regulator-1 activates the MAPK signaling pathway and induces proliferation and migration in human breast cancer MCF7 cells

Myofibrillogenesis regulator-1 (MR-1) has been characterized as a tumor promoter in many cancers. However, its mechanism of action has not been fully elucidated. Here, we report that MR-1 is over-expressed in human breast cancer cells and participates in tumor promotion in human breast cancer MCF7 cells by activating the ERK1/2 signaling pathway. MR-1 interacts with MEK1/2 and ERK1, and its N-terminal sequence plays a major role in promoting the MEK/ERK cascade. Furthermore, six phosphorylation sites of MR-1 were identified, and phosphorylation at S46 was shown to be critical for the activation of MEK/ERK. Therefore, our findings suggest that MR-1 functions as a tumor promoter in MCF7 cells by activating the MEK/ERK signaling. Structured summary of protein interactions: MR-1 physically interacts with ERK1 by anti tag coimmunoprecipitation (View interaction) ERK1 physically interacts with MR-1 by anti bait coip (1, 2) ERK1 and MR-1 colocalize by fluorescence microscopy (View interaction) (C) 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.