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In this report, we demonstrate that the mitochondrial ribosomal protein L41 (MRPL41) enhances p53 stability, and results in p53-induced apoptosis. An analysis of MRPL41 expression in paired normal and tumor tissues revealed lower expression in tumor tissue. Ectopic MRPL41 expression resulted in inhibition of the growth of cancer cells in tissue culture and tumor growth in nude mice. We discovered that MRPL41 protein is localized in the mitochondria, and stabilizes the p53 protein, and enhances its translocation to the mitochondria, thus inducing apoptosis. In the absence of p53, interestingly, MRPL41 stabilizes the p27Kip1 protein, and arrests the cell cycle at the G1 phase. These results suggest that MRPL41 exerts a tumor-suppressive effect in association with p53 and p27Kip1.

[Proc Amer Assoc Cancer Res, Volume 46, 2005]