Component of the SAS complex, a multiprotein complex that acetylates 'Lys-16' of histone H4 and 'Lys-14' of histone H3. The SAS complex is however unable to acetylate nucleosomal histones. The complex is involved in transcriptional silencing at telomeres and at HML locus. Also involved in rDNA silencing. In the complex, SAS5 is required for maximal histone acetyltransferase (HAT) activity of the complex, suggesting that it may be required to stabilize the complex or help in substrate recognition. Component of the SAS complex, at least composed of SAS2, SAS4 and SAS5. These three proteins constitute the core of the complex, and are sufficient to acetylate histones. Heterochromatin spreading downstream of the silent mating-type locus HMR. Present with 1800 molecules/cell in log phase SD medium.