first malignant brain tumor (MBT) repeat found in Polycomb protein sex comb on midleg homolog 1
Sex comb on midleg homolog 1 (SCMH1) is a homolog of Drosophila Sex comb on midleg (Scm). It is a component of PRC1 (Polycomb repressive complex 1), which acts as an E3 ubiquitin ligase, both for histone H2A to silence transcription and for geminin to regulate its stability. SCMH1 provides the complex with an interaction domain for geminin. It contains two MBT (malignant brain tumor) repeats. The MBT repeat is a protein module that recognizes methylated lysine residues on histones. MBT repeats contain a semi-aromatic cage to accommodate methyllysine and show specificity towards the lower methylation states of lysine. This model corresponds to the first MBT repeat that does not contain a semi-aromatic cage and may not bind methylated lysine residues.
Jiyao W et al.(2023). "The conserved domain database in 2023.",