SAP18

Description

The SAP18 (Sin3A associated protein 18) is a protein-coding gene located on chromosome 13.

Histone deacetylase complex subunit SAP18 is an enzyme that in humans is encoded by the SAP18 gene. Histone acetylation plays a key role in the regulation of eukaryotic gene expression. Multisubunit complexes catalyze histone acetylation and deacetylation. The protein encoded by this gene is a histone deacetylase complex component, including SIN3, SAP30, HDAC1, HDAC2, RbAp46, RbAp48, and other polypeptides. This protein directly interacts with SIN3 and enhances SIN3-mediated transcriptional repression when tethered to the promoter. Additionally, SAP18s splice variants are implicated in apoptotic cycles. SAP18 has been shown to interact with POLE2 and RGS10.

SAP18 is a component of the SIN3-repressing complex and enhances the ability of SIN3-HDAC1-mediated transcriptional repression. When tethered to the promoter, it can direct the formation of a repressive complex to core histone proteins. SAP18 is also an auxiliary component of the splicing-dependent multiprotein exon junction complex (EJC) deposited at splice junction on mRNAs. The EJC is a dynamic structure consisting of core proteins and several peripheral nuclear and cytoplasmic associated factors that join the complex only transiently either during EJC assembly or during subsequent mRNA metabolism. SAP18 is part of the ASAP and PSAP complexes, which bind RNA in a sequence-independent manner and are proposed to be recruited to the EJC prior to or during the splicing process to regulate specific excision of introns in specific transcription subsets. The ASAP complex can inhibit mRNA processing during in vitro splicing reactions and promotes apoptosis, being disassembled after induction of apoptosis. SAP18 is involved in the splicing modulation of BCL2L1/Bcl-X (and probably other apoptotic genes), specifically inhibiting the formation of proapoptotic isoforms such as Bcl-X(S). This activity is distinct from the established EJC assembly and function.

SAP18 is also known as 2HOR0202, SAP18P.

Associated Diseases

WES Whole Exome Sequencing