meiotic outer plaque

cellstructuremech:meiotic_outer_plaque · Cytoskeleton · Multiprotein complex · Proposed

A sporulation-specific cytoplasmic plaque that forms on meiosis II spindle pole bodies in budding yeast after outer-plaque remodeling and nucleates prospore membrane assembly. [DOI:10.1093/emboj/19.14.3657]

Synonyms: meiosis II outer plaque; MOP

Part of: spindle pole body (GO:0005816)

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

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding yeast is the characterized model in which sporulation-specific proteins remodel the cytoplasmic SPB outer plaque into a meiotic outer plaque. [DOI:10.1091/mbc.12.6.1611]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Budding-yeast MOP assembly, vesicle docking, and prospore membrane initiation have been dissected genetically and cytologically. [DOI:10.1091/mbc.E10-07-0563]

Functions

prospore membrane initiation — The meiotic outer plaque nucleates de novo prospore membrane formation on the cytoplasmic face of meiosis II spindle pole bodies.
- GO:0031322 GO:0031322 defines prospore-specific SPB remodeling as recruitment of sporulation-specific proteins to the outer plaque to form the MOP.
- DOI:10.1093/emboj/19.14.3657 Knop and Strasser 2000 analyzed the budding-yeast SPB outer plaque as the assembly site for prospore membranes.
prospore vesicle docking — The MOP acts as a docking complex for prospore-membrane precursor vesicles during Saccharomyces sporulation.
- DOI:10.1091/mbc.E10-07-0563 Mathieson et al. 2010 used Mpc54 mutants to separate vesicle association from docking at the MOP and linked docking to exocyst recruitment.

Mechanism graphs

MOP remodeling initiates the prospore membrane (ASSEMBLY)

During budding-yeast meiosis II, sporulation-specific remodeling converts the SPB outer plaque into a meiotic outer plaque that docks precursor vesicles and initiates prospore membrane growth.

Subject	Predicate	Object	Evidence
outer plaque of spindle pole body	is remodeled into	meiotic outer plaque	`GO:0031322` GO:0031322 defines ascospore-type prospore-specific SPB remodeling as recruitment of sporulation-specific proteins to form the MOP. `DOI:10.1091/mbc.12.6.1611` Bajgier et al. 2001 found that Spo21 is required for the meiosis-specific structural modification of the budding-yeast SPB outer plaque.
meiotic outer plaque	is part of	spindle pole body	`GO:0031322` GO:0031322 defines MOP formation as part of structural reorganization of the SPB outer plaque. `DOI:10.1093/emboj/19.14.3657` Knop and Strasser 2000 studied MOP formation on budding-yeast spindle pole bodies during meiosis.
meiotic outer plaque	anchors initiation of	prospore membrane	`DOI:10.1093/emboj/19.14.3657` Knop and Strasser 2000 linked MOP assembly at the SPB to prospore membrane formation. `DOI:10.1091/mbc.E10-07-0563` Mathieson et al. 2010 showed that the MOP docks precursor vesicles and recruits exocyst components during prospore membrane formation.

Discussions

INTERPRETATION (RESOLVED): Keep the meiotic outer plaque distinct from the general SPB outer plaque and the prospore-membrane SPB attachment site. GO:0031322 describes a meiosis II remodeling event that creates the MOP from the cytoplasmic SPB outer plaque, whereas GO:0005824 denotes the broader SPB outer plaque and GO:0070057 denotes the separate prospore-membrane region to which the SPB is anchored.
CURATION_TODO (OPEN): Resolve exact source-neutral family groundings for MOP constituents. The first MOP record captures the meiotic SPB outer-plaque specialization without guessing exact InterPro, Pfam, NCBIfam, or Complex Portal groundings for budding-yeast Mpc54, Spo21/Mpc70, Spo74, or Ady4.

Evidence

GO:0005824 Gene Ontology cellular-component term for the broader SPB outer plaque.
GO:0005816 Gene Ontology cellular-component term for the spindle pole body that carries the meiotic outer plaque.
GO:0031322 Gene Ontology biological-process term for ascospore-type prospore-specific SPB remodeling; its definition names meiotic outer plaque formation.
GO:0032120 Gene Ontology biological-process term for ascospore-type prospore membrane formation from the meiotic outer plaque.
GO:0005628 Gene Ontology cellular-component term for the prospore membrane that initiates from the meiotic outer plaque.
DOI:10.1093/emboj/19.14.3657 Knop and Strasser 2000, Role of the spindle pole body of yeast in mediating assembly of the prospore membrane during meiosis, The EMBO Journal.
DOI:10.1091/mbc.12.6.1611 Bajgier et al. 2001, SPO21 Is Required for Meiosis-specific Modification of the Spindle Pole Body in Yeast, Molecular Biology of the Cell.
DOI:10.1128/EC.2.3.431-445.2003 Nickas et al. 2003, Ady4p and Spo74p Are Components of the Meiotic Spindle Pole Body That Promote Growth of the Prospore Membrane in Saccharomyces cerevisiae, Eukaryotic Cell.
DOI:10.1091/mbc.E10-07-0563 Mathieson et al. 2010, Vesicle Docking to the Spindle Pole Body Is Necessary to Recruit the Exocyst During Membrane Formation in Saccharomyces cerevisiae, Molecular Biology of the Cell.

Curation history

2026-09-29T12:17:53Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-29T12:19:11Z codex · EXPANDED_RECORD — Added MOP synonymy, outer-plaque parentage, spindle-pole-body parthood, Saccharomyces scope, prospore-membrane initiation and vesicle-docking functions, GO and literature evidence, a nonmechanistic MOP remodeling graph, and boundary/component discussions.
2026-09-29T12:34:07Z codex · TIGHTENED_DEFINITION — Reworded the meiotic outer plaque definition so the record denotes the plaque structure rather than the remodeling process and used primary literature as the local definition source.
2026-10-11T15:29:00Z codex · ADDRESS_SAVED_REVIEW — Addressed #2221: Corrected the Nickas 2003 article-title phrase from Spores to Prospore Membrane, preserving the DOI and biological claims.

Source: data/structures/cytoskeleton/meiotic_outer_plaque.yaml