Chromobox protein homolog 3 (CBX3)

**Chromobox protein homolog 3 (CBX3 or HP1γ)** is a nonhistone chromosomal protein and key component of the heterochromatin protein 1 (HP1) family[1][2]. It binds specifically to histone H3 methylated at lysine 9 (H3K9me2/3) via its chromodomain, participating in the establishment and spread of heterochromatin regions, which leads to transcriptional silencing of genes[1][2][3]. CBX3 influences gene expression, chromatin organization, cell cycle progression, apoptosis, and is implicated in cancer progression. It interacts with various other nuclear proteins (e.g., lamin B receptor, PIM1, Ki-67, CBX5, CBX1) and can act as a scaffold for the recruitment of enzymatic modifiers of chromatin structure[1]. CBX3 is considered a promising but challenging therapeutic target in oncology and epigenetic drug development due to its multifaceted role in chromatin biology[2][3].

Other names

CBX3HP1γHeterochromatin protein 1 gammaHP1-gamma

Agents targeting CBX3 seek to modulate heterochromatin formation and epigenetic gene silencing, especially by interfering with its binding to methylated histones (e.g., H3K9me2/3) or disrupting protein-protein interactions fundamental to the formation of transcriptionally repressive chromatin[2][3].