| Category | Key points | Best supporting sources (citation IDs) | Publication year(s) and URL(s) when available |
|---|---|---|---|
| Identity | SWI1 in this report matches the *Saccharomyces cerevisiae* SWI/SNF chromatin-remodeling complex subunit encoded by **YPL016W**, also called **ADR6/GAM3**; it is a non-catalytic auxiliary subunit of the yeast SWI/SNF complex rather than the ATPase motor. | (pqac-00000003, pqac-00000004, pqac-00000005) | 2024 https://doi.org/10.1007/s00294-024-01300-x; 1994 https://doi.org/10.1007/BF00297274; 2023 https://doi.org/10.1080/19491034.2023.2165604 |
| Domains | Swi1 contains an **ARID/AT-rich interaction domain** spanning approximately **aa 405-506**; this domain has been reported to bind DNA **non-specifically**. An internal region **aa 329-657** interacts with activators, and mapping suggests **aa 507-606** contributes a core activator-binding region distinct from the ARID itself. | (pqac-00000000, pqac-00000001) | 2024 https://doi.org/10.1007/s00294-024-01300-x |
| Complex architecture | In cryo-EM reconstructions, Swi1 is a central structural subunit or “molecular nexus.” Its **N-terminus** contributes to the **substrate recruitment module (SRM)**, specifically the **DNA-binding lobe (DBL)** near nucleosomal exit DNA. The DBL includes **Snf6, Snf12, and the N-termini of Swi1 and Snf5**. A truncated construct containing **Swi1 residues 251-1336** was used for structure determination. | (pqac-00000006, pqac-00000007, pqac-00000008) | 2021 https://doi.org/10.1038/s41421-021-00262-5; 2024 https://doi.org/10.1098/rsob.240039 |
| Recruitment & activator binding | Swi1 functions as a **coactivator interface** that helps recruit SWI/SNF to promoters through transcriptional activators. It has documented interactions with activation domains from **Gcn4, VP16, Hap4**, and in 2024 work with **Ino2**; GST pull-down mapping showed Swi1 fragments containing **aa 428-606** bound Ino2 TAD1 efficiently, whereas **aa 329-531** did not, implying the ARID alone is insufficient for activator binding. | (pqac-00000001, pqac-00000002, pqac-00000003) | 2024 https://doi.org/10.1007/s00294-024-01300-x |
| Biological processes | As part of SWI/SNF, Swi1 supports **ATP-dependent chromatin remodeling** that opens promoter chromatin and helps generate **nucleosome-depleted regions** for transcription initiation. Classic genetic evidence links SWI1 to activation of genes such as **STE6** and to broader regulation of carbon-catabolite-responsive programs and other SWI/SNF-dependent genes. Yeast SWI/SNF overall has been estimated to regulate about **5% of genes**. | (pqac-00000003, pqac-00000004, pqac-00000005) | 2024 https://doi.org/10.1007/s00294-024-01300-x; 1994 https://doi.org/10.1007/BF00297274; 2023 https://doi.org/10.1080/19491034.2023.2165604 |
| Localization & site of action | Swi1 acts in the **nucleus**, associated with the **SWI/SNF complex on chromatin/nucleosomes**. Structurally it is positioned in the recruitment portion of the complex adjacent to **nucleosomal exit DNA**, and its N-terminus is proposed to help contact DNA directly or indirectly via transcription coactivators. | (pqac-00000005, pqac-00000006, pqac-00000008) | 2023 https://doi.org/10.1080/19491034.2023.2165604; 2021 https://doi.org/10.1038/s41421-021-00262-5 |
| Quantitative data | Quantitative details currently supported by available evidence include: yeast SWI/SNF has **~12 subunits**; regulates about **~5% of yeast genes**; cryo-EM map resolution was **6.9 Å overall**, with local resolution around **~3.6 Å** for the SRM and **~3.1 Å** near the nucleosome-facing region; Swi1 ARID is **aa 405-506**; activator-interacting region **aa 329-657**; efficient Ino2-TAD1-binding fragment **aa 428-606**. | (pqac-00000001, pqac-00000003, pqac-00000005, pqac-00000006) | 2024 https://doi.org/10.1007/s00294-024-01300-x; 2023 https://doi.org/10.1080/19491034.2023.2165604; 2021 https://doi.org/10.1038/s41421-021-00262-5 |


*Table: This table compiles the currently supported functional annotation for Saccharomyces cerevisiae Swi1/P09547, including identity verification, domain organization, structural role in SWI/SNF, recruitment mechanisms, biological roles, localization, and quantitative findings. It is useful as a compact evidence map before writing the full narrative report.*