mitotic spindle

GO:0072686 · Cytoskeleton · Other · Proposed

A spindle that forms as part of mitosis. Mitotic and meiotic spindles contain distinctive complements of proteins associated with microtubules. [GO:0072686]

Has part: spindle microtubule (GO:0005876)

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

Components

Component	Type	Part of / acts on	Grounding	Genes	Stoichiometry	Essential	Role
alpha- and beta-tubulins	Protein	part of	Reviewed label only (reviewed name; no accession asserted)			ESSENTIAL	Eukaryotic tubulin subunits that polymerize into the spindle microtubules of the mitotic spindle. `GO:0005876` Gene Ontology defines spindle microtubules as microtubules that are part of a mitotic or meiotic spindle. `GO:0005874` Gene Ontology defines microtubules as eukaryotic hollow tubes made from polymeric tubulin protofilaments. `DOI:10.1126/science.277.5325.574` Straight et al. 1997 imaged GFP-Tub1-labeled spindle microtubules in living Saccharomyces cerevisiae cells.

Taxonomic distribution

NCBITaxon:4932 Saccharomyces cerevisiae — COMMON: Budding yeast has a nuclear mitotic spindle whose microtubule organization has been reconstructed by serial-section electron microscopy. [DOI:10.1083/jcb.129.6.1601]

Canonical examples

NCBITaxon:4932 Saccharomyces cerevisiae — Reference microbial eukaryote in which mitotic spindle microtubules were reconstructed by serial-section electron microscopy. [DOI:10.1083/jcb.129.6.1601]

Functions

chromosome segregation GO:0007059 — Mitotic spindles move duplicated chromosomes apart by coupling kinetochores to spindle microtubules that extend from opposing spindle poles.
- GO:0005819 — spindle Gene Ontology defines the spindle as an array of microtubules and associated molecules that serves to move duplicated chromosomes apart.
- DOI:10.1126/science.277.5325.574 Straight et al. 1997 visualized chromosome movements and spindle dynamics in living budding-yeast cells.

Mechanism graphs

Spindle microtubules bridge budding-yeast spindle poles and kinetochores (FUNCTION)

In Saccharomyces cerevisiae, spindle pole bodies organize a bipolar array of spindle microtubules, and a subset of those microtubules attach to kinetochores during mitosis.

Subject	Predicate	Object	Evidence
spindle pole body	anchor	spindle microtubule	`GO:0005876` GO:0005876 defines spindle microtubules as part of a spindle and anchored at one spindle pole. `DOI:10.1146/annurev.cellbio.20.022003.114106` Jaspersen and Winey 2004 reviewed the budding-yeast SPB as the nuclear microtubule-organizing center.
spindle microtubule	assemble into	mitotic spindle	`GO:0005819` — spindle GO:0005819 defines the spindle as an array of microtubules and associated molecules between opposite poles. `DOI:10.1083/jcb.129.6.1601` Winey et al. 1995 reconstructed budding-yeast mitotic spindles from serial electron micrographs and classified their microtubule bundles.
spindle microtubule	attach to	kinetochore	`GO:0000776` GO:0000776 defines the kinetochore as a centromeric complex that provides an attachment point for spindle microtubules. `DOI:10.1083/jcb.129.6.1601` Winey et al. 1995 reconstructed budding-yeast spindles containing presumptive kinetochore microtubules and interpolar microtubules.

Discussions

INTERPRETATION (RESOLVED): Keep spindle pole bodies and kinetochores as adjacent structures instead of molecular components of the generic mitotic-spindle record. In budding yeast, spindle pole bodies organize spindle microtubules and kinetochores provide chromosome attachment sites for them, but both are separate GO-denoted structures with their own composition and curation boundaries rather than taxon-agnostic molecular constituents of GO:0072686.
CURATION_TODO (OPEN): Resolve exact source-neutral groundings for mitotic spindle motors and microtubule-associated proteins. GO defines spindles as microtubules plus associated molecules; this first record captures the alpha/beta-tubulin polymer boundary and defers the taxon-specific motor and microtubule-associated protein set.

Evidence

GO:0072686 Gene Ontology cellular-component term for the mitotic spindle.
GO:0005819 — spindle Gene Ontology cellular-component term for the broader spindle.
GO:0005876 Gene Ontology cellular-component term for the spindle microtubule.
GO:0005874 Gene Ontology cellular-component term for the microtubule.
GO:0007059 Gene Ontology biological-process term for chromosome segregation.
DOI:10.1083/jcb.129.6.1601 Winey et al. 1995, Three-dimensional ultrastructural analysis of the Saccharomyces cerevisiae mitotic spindle, Journal of Cell Biology.
DOI:10.1126/science.277.5325.574 Straight et al. 1997, Mitosis in Living Budding Yeast: Anaphase A But No Metaphase Plate, Science.
DOI:10.1146/annurev.cellbio.20.022003.114106 Jaspersen and Winey 2004 reviewed spindle pole body structure, duplication, and mitotic-spindle assembly in budding yeast.

Curation history

2026-09-18T23:15:22Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-18T23:16:16Z codex · EXPANDED_RECORD — Added spindle parentage and spindle-microtubule parthood, an alpha/beta-tubulin constituent, Saccharomyces cerevisiae scope, a chromosome-segregation function, GO and DOI evidence, a nonmechanistic budding-yeast spindle architecture graph, and discussions on SPB/kinetochore boundaries and MAP curation.
2026-09-18T23:16:44Z codex · NORMALIZED_GRAPH_LABELS — Normalized GO-grounded graph nodes to the canonical singular labels for spindle pole body, spindle microtubule, and kinetochore.
2026-09-18T23:26:49Z codex · FIX_DISCUSSION_ANCHOR — Pointed the spindle-associated-protein TODO at the alpha/beta-tubulin component anchor so every discussion reference resolves.
2026-09-18T23:34:36Z codex · ADDRESS_REVIEW — Resolved #1204 by reclassifying the SPB/microtubule/kinetochore graph as FUNCTION, and resolved #1205 by adding GO:0005874 evidence for alpha/beta-tubulin microtubule composition.
2026-09-23T20:01:52Z codex · ADD_SPINDLE_MICROTUBULE_CHILD — Linked GO:0005876 to its own spindle microtubule child record while preserving the budding-yeast spindle architecture graph on the parent.
2026-10-11T21:01:56Z codex · ADDRESS_SAVED_REVIEW — Addressed #2257: narrowed both Winey 1995 example notes to serial-section electron-microscopy reconstruction; preserved separately cited Straight 1997 live-cell evidence.

Source: data/structures/cytoskeleton/mitotic_spindle.yaml