SAS acetyltransferase complex

GO:0033255 · Other · Multiprotein complex · Proposed

A protein complex that possesses histone acetyltransferase activity and links histone acetylation to the assembly of transcriptionally silent chromatin. In vitro, the complex acetylates lysine 16 of histone H4 and lysine 14 of histone H3, although the latter may not be relevant in vivo. The complex contains a catalytic subunit and at least two other subunits; in Saccharomyces, the catalytic subunit is Sas2p and additional subunits are Sas4p and Sas5p. [GO:0033255]

Synonyms: SAS-I complex

UniProt location names: UniProt Consortium, CC BY 4.0. Reference label and route sources.

Components

Component	Type	Part of / acts on	Grounding	Genes	Essential	Role
Sas2 SAS-I catalytic subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SAS2	UNKNOWN	MYST-family histone acetyltransferase catalytic constituent of the budding-yeast SAS-I complex. `GO:0033255` GO:0033255 defines the Saccharomyces SAS acetyltransferase complex as containing catalytic Sas2p. `DOI:10.1101/gad.929001` Meijsing and Ehrenhofer-Murray 2001 found Sas2 in a nuclear protein complex with Sas4 and Sas5 and termed the complex SAS-I. `DOI:10.1074/jbc.M210709200` Sutton et al. 2003 reconstituted the SAS complex and showed that Sas2-dependent histone acetyltransferase activity requires Sas4 and is stimulated by Sas5.
Sas4 SAS-I subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SAS4	UNKNOWN	Protein constituent of the budding-yeast SAS-I complex that bridges Sas2p with Sas5p. `GO:0033255` GO:0033255 defines the Saccharomyces SAS acetyltransferase complex as containing Sas4p. `DOI:10.1074/jbc.M210709200` Sutton et al. 2003 showed that Sas4 is required for Sas2 histone acetyltransferase activity in the SAS complex. `DOI:10.1242/jcs.01739` Schaper et al. 2005 found that Sas4p is the central SAS-I subunit connecting Sas2p and Sas5p.
Sas5 SAS-I subunit	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SAS5	UNKNOWN	Protein constituent of the budding-yeast SAS-I complex that stimulates Sas2p histone acetyltransferase activity. `GO:0033255` GO:0033255 defines the Saccharomyces SAS acetyltransferase complex as containing Sas5p. `DOI:10.1101/gad.929001` Meijsing and Ehrenhofer-Murray 2001 identified Sas5 as part of the SAS-I complex. `DOI:10.1074/jbc.M210709200` Sutton et al. 2003 showed that Sas5 stimulates SAS-complex histone acetyltransferase activity.

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding yeast is the organism in which GO:0033255 defines the SAS-I complex as containing Sas2p, Sas4p and Sas5p. [GO:0033255]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Sutton et al. 2003 reconstituted the Sas2p/Sas4p/Sas5p SAS complex and compared it with native SAS complex purified from yeast. [DOI:10.1074/jbc.M210709200]

Functions

histone acetyltransferase activity GO:0004402 — The SAS-I complex acetylates histones through its Sas2 MYST-family catalytic subunit, with Sas4 required and Sas5 stimulating activity.
- GO:0033255 GO:0033255 defines SAS-I as a complex that possesses histone acetyltransferase activity.
- GO:0004402 GO:0004402 is the Gene Ontology molecular-function term for histone acetyltransferase activity.
- DOI:10.1074/jbc.M210709200 Sutton et al. 2003 assayed recombinant and native SAS complexes and reported Sas2-dependent histone acetyltransferase activity.

Mechanism graphs

SAS-I carries yeast histone acetyltransferase activity (FUNCTION)

In Saccharomyces cerevisiae, Sas2p, Sas4p and Sas5p form the SAS-I histone acetyltransferase complex.

Subject	Predicate	Object	Evidence
Sas2 SAS-I catalytic subunit	contributes to	SAS acetyltransferase complex	`GO:0033255` GO:0033255 defines Sas2p as the SAS-I catalytic subunit. `DOI:10.1101/gad.929001` Meijsing and Ehrenhofer-Murray 2001 found Sas2 in a Sas4/Sas5-containing nuclear protein complex.
Sas4 SAS-I subunit	contributes to	SAS acetyltransferase complex	`GO:0033255` GO:0033255 defines Sas4p as a SAS-I constituent. `DOI:10.1074/jbc.M210709200` Sutton et al. 2003 reconstituted the Sas2/Sas4/Sas5 SAS complex.
Sas5 SAS-I subunit	contributes to	SAS acetyltransferase complex	`GO:0033255` GO:0033255 defines Sas5p as a SAS-I constituent. `DOI:10.1101/gad.929001` Meijsing and Ehrenhofer-Murray 2001 identified Sas5 in SAS-I.
SAS acetyltransferase complex	supports	histone acetyltransferase activity	`GO:0033255` GO:0033255 defines the SAS complex as a histone acetyltransferase complex. `GO:0004402` GO:0004402 is the molecular-function term for histone acetyltransferase activity. `DOI:10.1074/jbc.M210709200` Sutton et al. 2003 showed that the reconstituted SAS complex acetylates histones.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral family groundings for the SAS-I constituents. GO:0033255 defines the budding-yeast Sas2p, Sas4p and Sas5p proteins as SAS-I complex constituents. Exact source-neutral InterPro, Pfam, NCBIfam or UniProt family boundaries for these SAS-I subunit classes need narrower curation before these component labels can be grounded.

Evidence

GO:0033255 Gene Ontology cellular-component term for the SAS acetyltransferase complex and its SAS-I complex exact synonym.
GO:0032777 Gene Ontology cellular-component parent term for piccolo histone acetyltransferase complexes.
GO:0004402 Gene Ontology molecular-function term for histone acetyltransferase activity.
PMID:11731480 PubMed identifier for Meijsing and Ehrenhofer-Murray 2001, the SAS-I complex discovery paper cited by GO:0033255.
DOI:10.1101/gad.929001 DOI for Meijsing and Ehrenhofer-Murray 2001, 'The silencing complex SAS-I links histone acetylation to the assembly of repressed chromatin by CAF-I and Asf1 in Saccharomyces cerevisiae', verified through NCBI E-utilities.
PMID:12626510 PubMed identifier for Sutton et al. 2003, the SAS-complex reconstitution and activity paper cited by GO:0033255.
DOI:10.1074/jbc.M210709200 DOI for Sutton et al. 2003, 'Sas4 and Sas5 are required for the histone acetyltransferase activity of Sas2 in the SAS complex', verified through NCBI E-utilities.
PMID:15788653 PubMed identifier for Schaper et al. 2005, the SAS-I nuclear-import paper cited by GO:0033255.
DOI:10.1242/jcs.01739 DOI for Schaper et al. 2005, 'Nuclear import of the histone acetyltransferase complex SAS-I in Saccharomyces cerevisiae', verified through NCBI E-utilities.

Curation history

2026-09-27T04:35:39Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-27T04:37:12Z codex · EXPANDED_RECORD — Added SAS-I exact synonymy, piccolo-histone-acetyltransferase-complex parentage, three budding-yeast SAS-I constituent rows, budding-yeast scope, histone acetyltransferase activity, GO/PubMed/DOI evidence, a nonmechanistic function graph, and a SAS-I subunit-grounding TODO.

Source: data/structures/other/sas_acetyltransferase_complex.yaml