The function of SINHCAF (SIN3-HDAC complex associated factor, Ensembl gene identifier ENSG00000139146) is as follows. Subunit of the Sin3 deacetylase complex (Sin3/HDAC), this subunit is important for the repression of genes encoding components of the TGF-beta signaling pathway (PubMed:22865885, PubMed:22984288). Core component of a SIN3A complex (composed of at least SINHCAF, SIN3A, HDAC1, SAP30, RBBP4, OGT and TET1) present in embryonic stem (ES) cells. Promotes the stability of SIN3A and its presence on chromatin and is essential for maintaining the potential of ES cells to proliferate rapidly, while ensuring a short G1-phase of the cell cycle, thereby preventing premature lineage priming (By similarity). {ECO:0000250|UniProtKB:Q8C8M1, ECO:0000269|PubMed:22865885, ECO:0000269|PubMed:22984288}.