first malignant brain tumor (MBT) repeat found in sex comb on midleg-like protein 2
Sex comb on midleg-like protein 2 (SCML2) 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. SCML2 is a germline-specific Polycomb protein that acts as a critical regulator of heterochromatin organization in spermatogenesis. SCML2 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.
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