PhuZ spindle

cellstructuremech:phuz_spindle · Cytoskeleton · Filament · Proposed

A phage-encoded tubulin-like cytoskeletal spindle assembled from PhuZ polymers that positions the jumbo-phage nucleus in infected bacterial cells. [DOI:10.1016/j.celrep.2017.07.064]

Synonyms: phage tubulin spindle

Part of: GO:0005856 — cytoskeleton (no local record)

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
PhuZ	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	phuZ		ESSENTIAL	Phage-encoded tubulin-like protein that polymerizes into dynamic filaments of bipolar spindles that position and can rotate jumbo-phage nuclei in infected Pseudomonas cells. `DOI:10.7554/eLife.03197` Erb et al. 2014 characterized Pseudomonas phage 201phi2-1 PhuZ as a dynamically unstable bacteriophage tubulin that forms filaments to position phage DNA during infection. `DOI:10.1016/j.celrep.2017.07.064` Chaikeeratisak et al. 2017 showed that dynamic PhuZ polymers form bipolar spindles associated with nucleus-like compartments in large Pseudomonas phages.

Taxonomic distribution

NCBITaxon:198110 Pseudomonas phage 201phi2-1 — COMMON: Pseudomonas phage 201phi2-1 uses PhuZ polymers to center replicating phage DNA during infection of Pseudomonas chlororaphis. [DOI:10.7554/eLife.03197]

Canonical examples

NCBITaxon:198110 Pseudomonas phage 201phi2-1 — Jumbo phage whose dynamically unstable PhuZ filaments established the phage-encoded tubulin spindle as a nucleus-positioning system. [DOI:10.7554/eLife.03197]

Functions

phage nucleus positioning — The PhuZ spindle pushes nucleus-like jumbo-phage replication compartments away from bacterial cell poles and toward midcell.
- DOI:10.7554/eLife.03197 Erb et al. 2014 linked PhuZ dynamic instability to centering phage DNA in Pseudomonas chlororaphis cells infected by 201phi2-1.
- DOI:10.1016/j.celrep.2017.07.064 Chaikeeratisak et al. 2017 connected dynamic PhuZ spindles with nucleus-like compartment positioning in PhiKZ and PhiPA3 infections.
phage nucleus rotation — The bipolar PhuZ spindle can rotate the phage nucleus during Pseudomonas phage 201phi2-1 infection, as opposing filaments act on opposite sides of the nucleus.
- DOI:10.1126/science.aal2130 Chaikeeratisak et al. 2017 Figure 1 and time-lapse experiments show nucleus movement and rotation with dynamic PhuZ; the static D190A mutant strongly disrupts both.

Mechanism graphs

PhuZ spindles position jumbo-phage nuclei (FUNCTION)

Phage-encoded PhuZ polymerizes into dynamic filaments of a bipolar spindle that positions the jumbo-phage nucleus in infected bacterial cells.

Subject	Predicate	Object	Evidence
PhuZ	polymerizes into	PhuZ spindle	`DOI:10.7554/eLife.03197` Erb et al. 2014 characterized PhuZ dynamic polymerization during 201phi2-1 infection. `DOI:10.1016/j.celrep.2017.07.064` Chaikeeratisak et al. 2017 observed PhuZ polymers forming bipolar spindle structures in infected cells.
PhuZ spindle	positions	phage nucleus	`DOI:10.1016/j.celrep.2017.07.064` Chaikeeratisak et al. 2017 linked PhuZ spindles with positioning of phage nucleus-like compartments in large Pseudomonas phages.
PhuZ spindle	supports	phage nucleus positioning	`DOI:10.7554/eLife.03197` Erb et al. 2014 connected PhuZ dynamic instability with centering of phage DNA in infected cells.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral grounding for phage PhuZ tubulins that build nucleus-associated cytoskeletal systems. This first record curates PhuZ proteins as phage-encoded tubulins that form nucleus-positioning spindles or nucleus-rotating vortex arrays without asserting that a broad FtsZ/tubulin-family domain or a virus-specific accession exactly denotes the full functional PhuZ family.
INTERPRETATION (RESOLVED): Chimallin and the phage nucleus are graph-scoped cargo rather than PhuZ spindle constituents. PhuZ forms the cytoskeletal spindle that positions the chimallin-lined phage nucleus; chimallin builds the separate shell and is not asserted as a constituent of the PhuZ polymer.
INTERPRETATION (RESOLVED): Keep the bipolar spindle distinct from the Goslar PhuZ cytoskeletal vortex. Earlier review issues #481 and #482 added Goslar occurrence and broadened PhuZ component wording to match the then-curated vortex rotation function. Birkholz et al. 2022 explicitly distinguish the Goslar vortex from a bipolar spindle and report that it does not center the nucleus at midcell. The existing record identifier, definition and positioning graph denote the spindle, not every PhuZ array.

Evidence

DOI:10.7554/eLife.03197 Erb, Kraemer, Coker, Chaikeeratisak, Nonejuie, Agard and Pogliano 2014, 'A bacteriophage tubulin harnesses dynamic instability to center DNA in infected cells', eLife.
DOI:10.1016/j.celrep.2017.07.064 Chaikeeratisak et al. 2017, 'The Phage Nucleus and Tubulin Spindle Are Conserved among Large Pseudomonas Phages', Cell Reports.
DOI:10.1016/j.celrep.2022.111179 Birkholz et al. 2022, A cytoskeletal vortex drives phage nucleus rotation during jumbo phage replication in E. coli, Cell Reports. Contrasting boundary evidence: Goslar forms a vortex rather than the bipolar spindle curated here.
GO:0005856 — cytoskeleton The containing cytoskeletal framework; this filament system is part of it, not a type of the whole framework.
DOI:10.1126/science.aal2130 Chaikeeratisak et al. 2017, Assembly of a nucleus-like structure during viral replication in bacteria, Science. Figure 1 supports spindle-mediated positioning and rotation in 201phi2-1 infection.

Curation history

2026-09-11T12:41:40Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-11T12:42:35Z codex · EXPANDED_RECORD — Added cytoskeleton parentage, PhuZ component curation, 201phi2-1 scope, phage nucleus positioning and rotation functions, DOI evidence, a nonmechanistic positioning graph, and PhuZ grounding and chimallin boundary discussions.
2026-09-11T12:50:19Z codex · REVIEW_FIX — Addressed PR review issues #481 and #482 by adding Goslar scope for the PhuZ rotation function and broadening PhuZ component/grounding wording from strictly nucleus-positioning to positioning-or-rotation cytoskeletal systems.
2026-10-11T17:56:38Z codex · ADDRESS_SAVED_REVIEW — Addressed #2234, #2235: Corrected cytoskeleton parthood and retained the specific filament-system identity. Separated the Goslar vortex into an explicit boundary discussion and grounded retained spindle rotation in primary 201phi2-1 experiments.

Source: data/structures/cytoskeleton/phuz_spindle.yaml