chromodomain of heterochromatin protein 1 homolog gamma
CHRomatin Organization Modifier (chromo) domain of heterochromatin protein 1 homolog gamma (also known as HP1gamma, Cbx3, and Chromobox 3), and related proteins. HP1gamma is a highly conserved non-histone protein, which is a member of the heterochromatin protein family, and is enriched in the heterochromatin and associated with centromeres. HP1 has two conserved protein-protein interaction domains, a single N-terminal chromodomain (CD) which can bind to histone proteins via methylated lysine residues, and a related C-terminal chromo shadow domain (CSD) which is responsible for the homodimerization and interaction with a number of chromatin-associated non-histone proteins; a flexible hinge region separates the CD and CSD and may bind nucleic acid. In addition to being involved in transcriptional silencing in heterochromatin-like complexes, HP1gamma also binds lamin B receptor, an integral membrane protein found in the inner nuclear membrane. The dual binding functions of the protein may explain the association of heterochromatin with the inner nuclear membrane. HP1gamma is also recruited to sites of ultraviolet-induced DNA damage and double-strand breaks. HP1 is a highly conserved non-histone chromosomal protein that is evolutionarily conserved from fission yeast to plants and animals. There are three human homologs of HP1 proteins: HP1alpha (also known as Cbx5), HP1beta (also known as Cbx1), and HP1gamma.
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