SIN3 transcription regulator family member A (SIN3A)

SIN3 transcription regulator family member A (SIN3A) is a large, highly conserved transcriptional co-regulator that acts as the central scaffold subunit of the multi-protein SIN3/HDAC histone deacetylase complex. It contains several paired amphipathic helix (PAH) domains and interacts with diverse chromatin-modifying enzymes, including HDAC1/2, and multiple transcription factors such as REST and MXD1-MAX heterodimers for gene repression. SIN3A complexes modulate gene expression by remodeling chromatin through histone deacetylation, and their genome-wide occupancy is found at many active promoters. The protein displays dual activity, functioning as both a transcriptional repressor and an activator depending on complex context and interacting partners. SIN3A is essential for vital biological processes, including regulation of the cell cycle, pluripotency, neuronal differentiation, circadian rhythms, and the transcriptional response to hypoxia. Germline mutations or deletions in SIN3A cause neurodevelopmental disorders like Witteveen-Kolk syndrome and are associated with chromosome 15q24 deletion syndrome. SIN3A-containing complexes are implicated in cancer, particularly through their regulation of MYC and cell cycle genes. While currently not a direct drug target, the essential role of SIN3A in chromatin regulation makes it a critical node in gene regulatory networks with both therapeutic promise and toxicity risk if modulated

Other names

Paired amphipathic helix protein Sin3aKIAA0700DKFZP434K2235Histone deacetylase complex subunit Sin3aTranscriptional corepressor Sin3aCHR15DELq24DEL15Q24WITKOSSIN3 homolog Atranscriptional co-repressor Sin3Atranscriptional coregulator Sin3a

Indirect mechanisms only—HDAC inhibitors disrupt the SIN3A-containing complexes by inhibiting their core enzymatic (HDAC1/2) activity, affecting gene repression