cellular bud neck polarisome

GO:0031560 · Other · Multiprotein complex · Proposed

Protein complex that has a role in determining cell polarity, found at the neck of a fungal bud before and during cytokinesis. [GO:0031560]

Part of: cellular bud neck (GO:0005935)

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
Spa2/Pea2 polarisome scaffold	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	SPA2, PEA2		CONDITIONAL	Scaffold proteins that localize to the mother-daughter neck before cytokinesis in budding Saccharomyces cells. `DOI:10.1083/jcb.135.3.725` Valtz and Herskowitz 1996 found that Pea2 relocalizes to the neck between mother and daughter cells before cytokinesis and reported that Pea2 follows the same general localization pattern as Spa2.

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding-yeast Pea2 and Spa2 polarity proteins localize to the mother-daughter neck late in mitosis before cytokinesis. [DOI:10.1083/jcb.135.3.725]

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast model in which Pea2 and Spa2 were localized to budding and mating polarity sites, including the neck between mother and daughter cells before cytokinesis. [DOI:10.1083/jcb.135.3.725]

bud-neck cell-polarity organization — The cellular bud neck polarisome is the GO-defined cell-polarity complex at the fungal bud neck, where Valtz and Herskowitz 1996 observed the Saccharomyces Spa2/Pea2 polarity scaffold before cytokinesis.
- GO:0031560 GO:0031560 defines the cellular bud neck polarisome by its role in cell-polarity determination at the neck of a fungal bud before and during cytokinesis.
- DOI:10.1083/jcb.135.3.725 Valtz and Herskowitz 1996 observed Pea2 at the Saccharomyces mother-daughter neck before cytokinesis and connected Pea2 with the similarly localized Spa2 polarity protein.

Spa2 and Pea2 mark the Saccharomyces mother-daughter neck occupied by the GO-defined bud-neck polarisome before cytokinesis.

Subject	Predicate	Object	Evidence
cellular bud neck polarisome	is part of	cellular bud neck	`GO:0031560` GO:0031560 defines this polarisome as being found at the neck of a fungal bud. `GO:0005935` GO:0005935 identifies the cellular bud neck.
Spa2/Pea2 polarisome scaffold	localizes to	cellular bud neck	`DOI:10.1083/jcb.135.3.725` Valtz and Herskowitz 1996 localized Pea2 to the mother-daughter neck before cytokinesis and described Pea2 and Spa2 localization as the same general pattern.
cellular bud neck polarisome	supports	bud-neck cell-polarity organization	`GO:0031560` GO:0031560 defines the bud-neck polarisome by its role in cell-polarity determination at the fungal bud neck.

CURATION_TODO (OPEN): Resolve exact source-neutral family groundings for the bud-neck Spa2/Pea2 scaffold. The first bud-neck polarisome record keeps Spa2 and Pea2 label-only rather than guessing InterPro, Pfam, or NCBIfam groundings whose broader homologous families may not exactly delimit the localized bud-neck scaffold.
CURATION_TODO (OPEN): Resolve whether Bni1, Bud6/Aip3, or other generic polarisome proteins are direct cellular-bud-neck polarisome constituents. GO:0000133 names Bni1p and Bud6p among Saccharomyces polarisome proteins, but the opened bud-neck-localization evidence in this first pass directly supports only Pea2 and Spa2 at the mother-daughter neck.

GO:0031560 Gene Ontology cellular-component term for the cellular bud neck polarisome.
GO:0000133 Gene Ontology cellular-component term for polarisome.
GO:0005935 Gene Ontology cellular-component term for the cellular bud neck.
DOI:10.1083/jcb.135.3.725 Valtz and Herskowitz 1996, 'Pea2 protein of yeast is localized to sites of polarized growth and is required for efficient mating and bipolar budding', Journal of Cell Biology.

2026-09-28T21:25:51Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-28T21:26:48Z codex · EXPANDED_RECORD — Added polarisome parentage, bud-neck parthood, a reviewed-label-only Spa2/Pea2 scaffold component, Saccharomyces distribution and canonical example evidence, a bud-neck polarity function, a nonmechanistic topology graph, and grounding and component-boundary TODOs.
2026-09-28T21:40:37Z codex · ADDRESSED_REVIEW — Resolved #1742 by retargeting the Spa2/Pea2 topology edge from the GO:0031560 complex to the GO:0005935 bud-neck site and separating DOI-backed neck localization from GO-backed complex identity in the function and graph text.