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Updated: Jun 4, 2026

Sequence-specific Labeling of Nucleic Acids and Proteins with Methyltransferases and Cofactor Analogues
Published on: November 22, 2014
Methionine adenosyltransferase II serves as a transcriptional corepressor of Maf oncoprotein
Yasutake Katoh1, Tsuyoshi Ikura, Yutaka Hoshikawa
1Department of Biochemistry, Tohoku University Graduate School of Medicine, Sendai, Miyagi 980-8575, Japan.
Abstract:
Protein methylation pathways comprise methionine adenosyltransferase (MAT), which produces S-adenosylmethionine (SAM) and SAM-dependent substrate-specific methyltransferases. However, the function of MAT in the nucleus is largely unknown. MafK represses or activates expression of heme oxygenase-1 (HO-1) gene, depending on its heterodimer partners. Proteomics analysis of MafK revealed its interaction with MATIIα, a MAT isozyme. MATIIα was localized in nuclei and found to form a dense network with chromatin-related proteins including Swi/Snf and NuRD complexes. MATIIα was recruited to Maf recognition element (MARE) at HO-1 gene. When MATIIα was knocked down in murine hepatoma cell line, expression of HO-1 was derepressed at both basal and induced levels. The catalytic activity of MATIIα, as well as its interacting factors such as MATIIβ, BAF53a, CHD4, and PARP1, was required for HO-1 repression. MATII serves as a transcriptional corepressor of MafK by interacting with chromatin regulators and supplying SAM for methyltransferases.
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