APC2 (S. cerevisiae, Q12440) - review notes

Identity

• YLR127C / RSI1 / APC2; 853 aa; cullin family (UniProt PROSITE ProRule PRU00330). Ortholog of human ANAPC2.
• Founding papers: Kramer et al. 1998 PMID:9430641 and Zachariae et al. 1998 PMID:9469814.
• Inputs used: UniProt record, GOA tsv, falcon deep research (Edison), cached publications. Abstract-only in cache: PMID:9430641, PMID:9469814, PMID:12477395, PMID:12609981. Full text: PMID:16481473, PMID:11114178, PMID:19109423, PMID:37968396, PMID:10888670, PMID:19822757. Not cached (cited only via the deep-research file): Melloy & Holloway 2004 Genetics (Cdc23/Apc9 localisation), Vazquez-Fernandez et al. 2024 eLife (yeast APC/C cryo-EM), Rodrigo-Brenni & Morgan 2007 (Ubc4/Ubc1 K48 chains).

Molecular role

• Apc2 + Apc11 = cullin-RING catalytic core; Apc1 bridges the Apc2/Apc11/Doc1 subcomplex to the TPR subcomplex PMID:16481473.
• apc2 delta loses Apc11 and Doc1 completely; apc11 delta only partially reduces Apc2/Doc1 PMID:16481473.
• Apc2 needed for Cdh1 binding (10-fold drop in apc2 delta) PMID:16481473.
• apc2 delta APC/C has no detectable ligase activity in vitro PMID:16481473.
• Apc11 alone transfers ubiquitin; Apc2 not required in the minimal system, proposed to tether/position Apc11 PMID:10888670. Hence contributes_to (not enables) for GO:0061630, and the NEW GO:0160072 ubiquitin ligase complex scaffold activity row (same term used for human ANAPC2 in this repo).
• Chain linkage: yeast APC/C uses Ubc4 (initiation) and Ubc1 (elongation) and builds K48 chains; no Ube2S ortholog PMID:19822757. This is the basis for MODIFY of the K11 IBA (GO:0070979 -> GO:0070936 / GO:0000209).
• Deep research: yeast Apc2 lacks the 45-residue four-cysteine zinc-binding insert of human APC2; apo yeast APC/C already holds the Apc2:Apc11 module in an E2-compatible position (Vazquez-Fernandez 2024, via deep-research file).

Biological outputs

• Metaphase/anaphase: rsi1/apc2 ts arrest bypassed by pds1 delta PMID:9430641.
• Mitotic exit: Clb2 stabilised; sic1 delta synthetic lethal PMID:9430641; rsi1-8 pds1 delta cells arrest in telophase (deep-research summary of the full text).
• Securin and B-type cyclins are the only obligatory APC/C targets PMID:16481473.
• Cytokinesis: apc2 delta (APC-nonessential background) delays Myo1 disassembly after ring contraction; contraction itself is normal without Cdh1 PMID:19109423. GO:1903473 (positive regulation of ring contraction) therefore misfits; MODIFY to GO:0044837, following the CDH1 review precedent.
• Meiosis: Ama1 is the meiotic coactivator PMID:11114178; Apc2 is present in meiotic APC/C preparations PMID:12609981. No Apc2-specific meiotic data -> KEEP_AS_NON_CORE for GO:0051445.

Localisation

• UniProt (Huh 2003 GFP): cytoplasm and nucleus. Tagged Cdc23/Apc9 predominantly nuclear with kinetochore/spindle foci (Melloy 2004, via deep-research file). Nucleus accepted as core site; cytoplasm kept non-core.

Curation decisions (summary)

• GO:0005515 x3 (IntAct, Mnd2): REMOVE per protein-binding policy; the pairs are co-complex membership (Hall 2003 lists Cdc23/Apc5/Apc1, not Apc2, as direct Mnd2 partners PMID:12609981).
• GO:0005680 x5, GO:0007091 x2, GO:0010458, GO:0016567 x5, GO:0031145 x5, GO:0061630 (contributes_to), GO:0005634: ACCEPT.
• GO:0005737, GO:0051445: KEEP_AS_NON_CORE.
• GO:0007346 (ComplexPortal NAS): MODIFY -> GO:0007091 + GO:0010458 (too shallow).
• GO:0070979 IBA: MODIFY -> GO:0070936 / GO:0000209 (lineage divergence; propagation_review recorded).
• GO:1903473 IMP: MODIFY -> GO:0044837.
• NEW: GO:0160072 ubiquitin ligase complex scaffold activity, IDA PMID:16481473.