Menin (E5P1R) Rabbit mAb #19893

Mutations in the MEN1 tumor suppressor gene cause multiple endocrine neoplasia type 1 (MEN1), an autosomal dominant familial tumor syndrome typified by tumors of the pituitary, parathyroid, lung, and enteropancreatic endocrine tissues (1,2). Patients with this tumor syndrome have inherited either missense or truncation mutations in one allele of the MEN1 gene, while the other allele is subject to loss of heterozygosity in tumors from these patients (1,2). Menin, the protein product of the MEN1 gene, is a component of the mixed-lineage leukemia protein (MLL)-containing histone methyltransferase complex that facilitates methylation of histone H3 Lys4 to promote transcriptional activation (3,4). Menin functions to suppress proliferation of pancreatic islet cells, at least in part through MLL-mediated activation of the p18 and p27 cyclin-dependent kinase inhibitor genes (5,6). Loss of Menin leads to a decrease in methylation of histone H3 Lys4 and decreased expression of the p18 and p27 genes, leading to hyperplasia (5,6). In contrast to its role as a tumor suppressor in endocrine cells, Menin has been shown to promote proliferation in leukemia cells driven by MLL-fusion proteins. Menin is essential for oncogenic MLL-fusion-protein-mediated transformation of bone marrow cells and is required for histone H3 Lys4 methylation and expression of the HoxA9 gene (7,8). Menin interacts with a wide range of proteins, including JunD, SMAD family members, estrogen receptor, vitamin D receptor, PEM, NFκB, FANCD2, RPA2, NMMHC II-A, GFAP, vimentin, and HSP70, suggesting additional roles in transcriptional regulation, DNA processing and repair, cytoskeleton organization, and protein degradation (9,10).