Chromobox protein homolog 5 (CBX5)

Chromobox protein homolog 5 (CBX5), also known as HP1α, is a highly conserved, non-histone chromatin protein that functions as a key component of constitutive heterochromatin in eukaryotic cells[1][2][3]. CBX5 contains an N-terminal chromodomain that specifically binds trimethylated lysine 9 on histone H3 (H3K9me3), resulting in epigenetic repression and gene silencing[2][3]. The C-terminal chromoshadow domain mediates homodimerization and interaction with other chromatin-associated proteins, supporting the formation and maintenance of repressive chromatin domains and facilitating the assembly of heterochromatin at centromeres and telomeres[1][2][3][4]. CBX5 plays essential roles in genome stability, kinetochore and centromere function during cell division, and DNA damage response, and its dysregulation has been implicated in cancer and other diseases linked to chromatin dysfunction and genome instability[1][2][3]. Notes: - CBX5 itself is not commonly regarded as a classical therapeutic target (e.g., not a receptor, enzyme, transporter, or a routinely drugged protein), but its fundamental roles in epigenetic regulation and frequent upregulation in cancer make it a protein of high biological interest[1][2][3]. - No approved drugs currently directly target CBX5; manipulation of CBX5 or HP1α function is generally indirect, via modulation of histone methylation or chromatin states, which can have broad effects on chromatin and gene expression[1][2].

Other names

HP1αHP1AHP1 alphaHP1HP1-ALPHAHP1alphaAntigen p25HEL25heterochromatin protein 1 homolog alphaepididymis luminal protein 25HP1Hs-alphaHP1Hs alphachromobox homolog 5 (HP1 alpha homolog, Drosophila)