id: Pfam:PF05591
pfam_id: PF05591
name: Type VI secretion system, VipA, VC_A0107 or Hcp2
short_name: T6SS_VipA
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF05591
counters:
  proteins: 4990
  matches: 5021
  proteomes: 3299
  taxa: 4768
  structures: 11
  alphafold_models: 3141
  domain_architectures: 12
provenance:
  snapshot_id: interpro-pfam-duf-2026-10-10
  path: data/worklists/interpro-pfam-duf-2026-10-10.json
  sha256: 17fb625876c9326ed284263a47bcd84e0d7844a31c040dc06cd2260c36f1c383
  generated_at: '2026-10-10T07:44:21.614711Z'
  source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/
interpro_id: InterPro:IPR008312
description: T6SSs are toxin delivery systems. It is a multiprotein complex requiring numerous core proteins
  (Tss proteins) including cytoplasmic, transmembrane, and outer membrane components. The needle or tube
  apparatus is comprised of a phage-like complex, similar to the T4 contractile bacteriophage tail, which
  is thought to be anchored to the membrane by a trans-envelope complex [[cite:PUB00090998]]. VipA is
  a family of Gram-negative bacterial proteins that form part of the type VI pathogenic secretion system.
  Members have been variously defined as VC_A0107 family, Hcp2, TssB and VipA, for ClpV-interacting proteins.
  VipB and VipA proteins interact very closely to form the shaft of the pathogenic penetrating needle
  system [[cite:PUB00075705],[cite:PUB00075433],[cite:PUB00075706]]. VipA and VipB (TssB and TssC) proteins
  were shown to form a cog-wheel like tubular structure in V. cholerae that was noticed to resemble T4
  phage gp18 polysheath. Two beta-strands of VipA and four beta-strands of VipB intertwine forming the
  middle layer of the sheath. The sheath assembles around an inner Hcp tube and is attached to a structure
  called a baseplate that spans the bacterial membranes. Importantly, VipA/VipB sheath was shown to form
  a long contractile organelle in V. cholerae and in E. coli, suggesting that sheath contraction powers
  the secretion [[cite:PUB00091000]].