Faculty, Staff and Student Publications

Language

English

Publication Date

1-2-2026

Journal

FEMS Microbiology Reviews

DOI

10.1093/femsre/fuaf069

PMID

41474020

PMCID

PMC12857230

PubMedCentral® Posted Date

12-31-2025

PubMedCentral® Full Text Version

Post-print

Abstract

Type IV secretion systems (T4SS) are versatile nanomachines responsible for the transfer of DNA and proteins across cell envelopes. From their ancestral role in conjugation, these systems have diversified into a superfamily with functions ranging from horizontal gene transfer to the delivery of toxins to eukaryotic and prokaryotic hosts. Recent structural and functional studies have uncovered unexpected architectural variations not only among Gram-negative systems but also between Gram-negative and Gram-positive systems. Despite this diversity, a conserved set of core proteins is maintained across the superfamily. To facilitate cross-system comparisons, we propose in this review a unified nomenclature for conserved T4SS subunits found in both Gram-negative and Gram-positive systems. We further highlight conserved and divergent mechanistic and architectural principles across bacterial lineages, and we discuss the diversity of emerging T4SSs whose unique structures and functions expand our understanding of this highly adaptable secretion superfamily.

Keywords

Type IV Secretion Systems, Terminology as Topic, Gram-Negative Bacteria, Bacterial Proteins, Gram-Positive Bacteria, Type IV secretion systems (T4SSs), horizontal gene transfer, conjugation, effectors secretion, relaxosome, nomenclature

Published Open-Access

yes

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