2l7p
From Proteopedia
ASHH2 a CW domain
Structural highlights
Function[ASHH2_ARATH] Histone methyltransferase involved in di and tri-methylation of 'Lys-36' of histone H3 (H3K36me2 and H3K36me3). Binds to H3 already mono- or di-methylated on 'Lys-4'(H3K4me1 or H3K4me2), but not to H3K4me3. H3K4me and H3K36me represent specific tags for epigenetic transcriptional activation. Regulates positively FLC transcription to prevent early flowering transition. Required for flowering transition in response to vernalization and for the maintenance of FLC expression in late embryos, but dispensable for the initial reactivation in early embryos during reprogramming. Seems also to modulate several traits including floral organ size, root size and dormancy. Promotes apical dominance (PubMed:16299497, PubMed:10518493, PubMed:16258034, PubMed:18070919, PubMed:19915673, PubMed:20711170). Directly involved in the tri-methylation of 'Lys-36' of histone H3 (H3K36me3) at LAZ5 chromatin to maintain a transcriptionally active state of LAZ5, a TIR-NB-LRR protein involved in innate immunity (PubMed:20949080).[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedPost-translational modifications of the N-terminal histone tails, including lysine methylation, have key roles in regulation of chromatin and gene expression. A number of protein modules have been identified that recognize differentially modified histone tails and provide their proteins with the capacity to sense such modifications. Here, we identify the CW domain of plant and animal chromatin-related proteins as a novel module that recognizes different methylated states of lysine 4 on histone H3 (H3K4me). The solution structure of the CW domain of the Arabidopsis ASH1 HOMOLOG2 (ASHH2) histone methyltransferase provides insight into how different CW domains can distinguish different methylated histone tails. We provide evidence that ASHH2 is acting on H3K4me-marked genes, allowing for ASHH2-dependent H3K36 tri-methylation, which contributes to sustained expression of tissue-specific and developmentally regulated genes. This suggests that ASHH2 is a combined 'reader' and 'writer' of the histone code. We propose that different CW domains, dependent on their specificity for different H3K4 methylations, are important for epigenetic memory or participate in switching between permissive and repressive chromatin states. The CW domain, a new histone recognition module in chromatin proteins.,Hoppmann V, Thorstensen T, Kristiansen PE, Veiseth SV, Rahman MA, Finne K, Aalen RB, Aasland R EMBO J. 2011 Apr 26. PMID:21522130[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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