M-phase phosphoprotein 8 (MPHOSPH8)

M-phase phosphoprotein 8 (MPHOSPH8, commonly abbreviated as MPP8) is a chromatin-associated protein that acts as a key epigenetic regulator, primarily by serving as a central member of the human silencing hub (HUSH) complex[1][2][3]. MPHOSPH8 contains an N-terminal chromodomain that specifically binds methylated lysine 9 of histone H3 (H3K9me2/3), facilitating recruitment of chromatin-modifying enzymes—including histone methyltransferases (SETDB1, G9a/GLP), DNA methyltransferases (DNMT3A), and histone deacetylases (SIRT1)—that enforce transcriptional silencing through heterochromatin formation, DNA methylation, and downstream repressive modification of gene promoters[1][2][3][5]. MPHOSPH8 is essential for epigenetic regulation of ground-state pluripotency in stem cells, acts as a gatekeeper for repression of transposable elements (such as LINE1 retrotransposons), and helps regulate cell cycle arrest and differentiation[2][3]. Aberrant MPHOSPH8 activity or overexpression has been implicated in multiple cancers, supporting cell proliferation, migration, invasion, and possibly promoting epithelial-to-mesenchymal transition through repression of tumor suppressor genes and modulation of key signaling pathways (e.g., p38 MAPK and HOXA5)[1]. Structurally, MPHOSPH8 is composed of a chromodomain and multiple ankyrin-repeat domains—the former mediating histone binding and the latter participating in protein–protein interactions, including complex formation with other HUSH subunits (e.g., TASOR and PPHLN1). No drugs or drug mechanisms are currently annotated for MPHOSPH8, and no established clinical biomarkers or safety concerns are reported[3][5].

Other names

MPHOSPH8MPP8TWA3HSMPP8Two hybrid-associated protein 3 with RanBPMmpp8

Not applicable—no drugs directly targeting M-phase phosphoprotein 8 are currently listed in major databases