PopZ polar microdomain

cellstructuremech:popz_polar_microdomain · Other · Subcellular region · Proposed

A proteinaceous bacterial polar microdomain formed by PopZ polymers at Caulobacter cell poles that anchors the ParB-bound chromosomal origin and organizes pole-specific client proteins. [DOI:10.1016/j.cell.2008.07.015]

Synonyms: Caulobacter PopZ polar subdomain

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
PopZ	Protein	part of	Reviewed label only (reviewed name; no accession asserted)	popZ		UNKNOWN	Self-associating polar organizer that polymerizes into the ribosome-excluding microdomain matrix at Caulobacter cell poles. `DOI:10.1016/j.cell.2008.07.015` Bowman et al. 2008 identified PopZ as a polymeric polar protein that anchors the ParB-bound chromosomal origin complex. `DOI:10.1016/j.cell.2008.07.016` Ebersbach et al. 2008 independently characterized PopZ as a self-associating polar protein needed for polar organization in Caulobacter.

Taxonomic distribution

NCBITaxon:155892 Caulobacter vibrioides — COMMON: The PopZ polar microdomain has been experimentally characterized in Caulobacter crescentus, now classified as Caulobacter vibrioides. [DOI:10.1016/j.cell.2008.07.015]

Canonical examples

NCBITaxon:565050 Caulobacter vibrioides NA1000 — Standard Caulobacter strain used to define PopZ-dependent polar microdomain localization and chromosomal-origin anchoring. [DOI:10.1111/j.1365-2958.2010.07088.x]

Functions

chromosomal-origin anchoring — The PopZ polar microdomain anchors the ParB-bound chromosomal origin region at the Caulobacter cell pole.
- DOI:10.1016/j.cell.2008.07.015 Bowman et al. 2008 connected PopZ polymers to anchoring of the chromosomal origin/ParB complex at a bacterial cell pole.
pole-specific client-protein organization — The PopZ polar microdomain serves as a hub for multiple client proteins that contribute to sequential changes in Caulobacter pole composition.
- DOI:10.1111/j.1365-2958.2010.07088.x Bowman et al. 2010 showed that the PopZ polar subdomain organizes sequential changes in pole composition and function.
- DOI:10.1073/pnas.1602380113 Holmes et al. 2016 identified PopZ as an intrinsically disordered hub for organizing bacterial cell poles.

Mechanism graphs

PopZ polymers organize Caulobacter cell poles (FUNCTION)

PopZ self-associates into a polar microdomain that localizes at Caulobacter cell poles, anchors the ParB-bound origin region, and binds a representative regulatory client.

Subject	Predicate	Object	Evidence
PopZ	self-associates into	PopZ polar microdomain	`DOI:10.1016/j.cell.2008.07.016` Ebersbach et al. 2008 characterized PopZ as a self-associating polar protein. `DOI:10.1073/pnas.1602380113` Holmes et al. 2016 analyzed PopZ network formation at Caulobacter cell poles.
PopZ polar microdomain	localizes to	Caulobacter cell pole	`DOI:10.1111/j.1365-2958.2010.07088.x` Bowman et al. 2010 described PopZ as a polar subdomain of Caulobacter.
PopZ polar microdomain	anchors	ParB-bound chromosomal origin anchoring complex	`DOI:10.1016/j.cell.2008.07.015` Bowman et al. 2008 linked PopZ polymers to polar anchoring of the chromosomal origin/ParB complex.
PopZ	directly binds	CpdR	`DOI:10.1073/pnas.1602380113` Holmes et al. 2016 identified direct binding between PopZ and multiple client proteins, including CpdR.

Discussions

CURATION_TODO (OPEN): Resolve exact source-neutral grounding for full-length matrix-forming PopZ proteins. This first record curates Caulobacter PopZ without asserting that a broad low-complexity or coiled-coil domain accession exactly denotes the whole polar-microdomain protein family.

Evidence

DOI:10.1016/j.cell.2008.07.015 Bowman, Comolli, Zhu, Eckart, Koenig et al. 2008, 'A Polymeric Protein Anchors the Chromosomal Origin/ParB Complex at a Bacterial Cell Pole', Cell.
DOI:10.1016/j.cell.2008.07.016 Ebersbach, Briegel, Jensen and Jacobs-Wagner 2008, 'A Self-Associating Protein Critical for Chromosome Attachment, Division, and Polar Organization in Caulobacter', Cell.
DOI:10.1111/j.1365-2958.2010.07088.x Bowman, Comolli, Gaietta, Fero et al. 2010, 'Caulobacter PopZ forms a polar subdomain dictating sequential changes in pole composition and function', Molecular Microbiology.
DOI:10.1073/pnas.1602380113 Holmes, Follett, Wang, Meadows, Varga and Bowman 2016, 'Caulobacter PopZ forms an intrinsically disordered hub in organizing bacterial cell poles', PNAS.

Curation history

2026-09-11T10:52:35Z codex · CREATED_RECORD — Scaffolded by scripts/new_record.py
2026-09-11T10:53:11Z codex · EXPANDED_RECORD — Added cell-part parentage, PopZ polar-subdomain synonymy and component curation, Caulobacter vibrioides scope, chromosomal-origin anchoring and pole-organization functions, DOI evidence, a nonmechanistic PopZ polar-organization graph, and a PopZ grounding TODO.
2026-09-11T11:02:59Z codex · REVIEW_FIX — Addressed PR #464 review issues #465, #466, and #467 by removing an unsupported PopZ organizing-matrix synonym, narrowing PopZ essentiality to UNKNOWN, and tightening the PopZ graph's ParB-origin and client-protein boundary nodes.
2026-09-11T11:03:15Z codex · REVIEW_FIX — Adjusted PopZ graph scope notes to match the PR #464 fix for review issue #467.
2026-09-11T11:12:22Z codex · FIX_OBSOLETE_PARENT — Addressed PR #464 CI issue #468 by replacing obsolete parent GO:0044464 with live GO:0110165.

Source: data/structures/other/popz_polar_microdomain.yaml