id: Pfam:PF03398
pfam_id: PF03398
name: Regulator of Vps4 activity in the MVB pathway
short_name: Ist1
seed_status: EX_DUF
characterization_status: UNSCORED
curation_status: SEEDED
source_url: https://www.ebi.ac.uk/interpro/api/entry/pfam/PF03398
counters:
  proteins: 9996
  matches: 10247
  proteomes: 3256
  taxa: 8671
  structures: 12
  alphafold_models: 8194
  domain_architectures: 140
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:IPR005061
description: ESCRT-I, -II, and -III are endosomal sorting complexes required for transporting proteins
  and carry out cargo sorting and vesicle formation in the multivesicular bodies, MVBs, pathway. These
  complexes are transiently recruited from the cytoplasm to the endosomal membrane where they bind transmembrane
  proteins previously marked for degradation by mono-ubiquitination. Assembly of ESCRT-III, a complex
  composed of at least four subunits (Vps2, Vps24, Vps20, Snf7), is intimately linked with MVB vesicle
  formation, its disassembly being an essential step in the MVB vesicle formation, a reaction that is
  carried out by Vps4, an AAA-type ATPase. The family Ist1 is a regulator of Vps4 activity; by interacting
  with Did2 and Vps4, Ist1 appears to regulate the recruitment and oligomerisation of Vps4. Together Ist1,
  Did2, and Vta1 form a network of interconnected regulatory proteins that modulate Vps4 activity, thereby
  regulating the flow of cargo through the MVB pathway [[cite:PUB00109174]].