PAX3- and PAX7-binding protein 1 (PAXBP1)

PAX3- and PAX7-binding protein 1 (PAXBP1) is a nuclear adaptor protein that bridges the transcription factors PAX3 and PAX7 to the histone methylation machinery, specifically interacting with complexes that mediate dimethylation and trimethylation of lysine-4 on histone H3 (H3K4)[1][2]. This role allows PAXBP1 to integrate epigenetic control with developmental gene expression, crucially regulating muscle precursor cell (myoblast and muscle satellite cell) proliferation and the transition from quiescence to cell cycle reentry in response to muscle injury[1][2][4]. PAXBP1 functions upstream in pathways controlling cerebellar development, skeletal muscle formation, craniofacial development, and spine morphogenesis[1][3][4]. Loss-of-function mutations in PAXBP1 are linked to rare syndromes of global developmental delay and myopathic hypotonia. Mechanistic studies show PAXBP1 controls cell cycle checkpoints via regulation of mTORC1 activity and reactive oxygen species, with loss resulting in p53 activation, cell cycle arrest, apoptosis, and failure of muscle regeneration[4]. There are currently no known drugs directly targeting PAXBP1, and it is not considered a classical therapeutic target, but its essential developmental and regulatory roles have made it of interest in rare genetic disorders and muscle biology.

Other names

FSAP105GCFC1BM020C21orf66GCFCPAX3 and PAX7 binding protein 1GC-rich sequence DNA-binding factor 1functional spliceosome-associated protein 105GC-rich sequence DNA-binding factor candidate