Trithorax Related Protein 4 (ATXR4)

Trithorax Group (TrxG) proteins typically function in large complexes formed with other proteins. The complexes formed by TrxG proteins are divided into 2 groups: Histone-modifying complexes and ATP-dependent chromatin-remodeling complexes. The main function of TrxG proteins, along with polycomb group (PcG) proteins, is regulating gene expression. Whereas, PcG proteins are typically associated with gene silencing, TrxG proteins are most commonly linked to gene activation. The Trithorax complex activates gene transcription by inducing trimethylation of lysine 4 of histone H3 (H3K4me3) at specific sites in chromatin recognized by the complex. Ash1 domain is involved in H3K36 methylation. Trithorax complex also interacts with CBP (CREB binding protein) which is an acteyltransferase to acetylate H3K27.