Protein polybromo-1 (PBRM1) (PBRM1)

Protein polybromo-1 (PBRM1), also known as BAF180 or Pb1, is a key subunit of the PBAF chromatin remodeling complex, which is a variant of the SWI/SNF family involved in altering DNA-nucleosome topology to regulate gene expression. It features six tandem bromodomains that recognize acetylated histone lysine residues, two bromo-adjacent homology (BAH) domains for protein interactions, and a high-mobility group (HMG) domain that likely binds nucleosomal DNA, enabling chromatin targeting, subunit recruitment, and structural alterations essential for processes like mitosis and estrogen-responsive gene transcription. As a tumor suppressor, PBRM1 mutations are prevalent in clear cell renal cell carcinoma (ccRCC), often co-occurring with VHL loss to enhance HIF1α signaling and NF-κB pathways, promoting tumorigenesis. Despite its role, no approved drugs directly target PBRM1, though its mutation status is explored as a potential biomarker for immunotherapy response in advanced ccRCC, with ongoing debate on prognostic value. Isoforms arising from alternative splicing may modulate domain composition, potentially influencing targeting specificity and complex assembly.

Other names

BAF180BRG1-associated factor 180Pb1