{
  "abstract": "Giant unilamellar vesicles (GUVs) are a powerful model system for studying protein dynamics in cell-sized compartments with a precisely tunable physicochemical environment. Here, we apply Single-Molecule Displacement Mapping (SMdM) to quantify how luminal viscosity, ionic strength, membrane lipid composition, and protein surface charge of soluble proteins govern intraluminal single-molecule diffusion. Increasing viscosity led to a predictable decrease in the diffusion coefficient. However, spatially resolved diffusion measurements reveal reduced protein mobility near the membrane, suggesting additional membrane-proximal interactions not captured by particle-based simulations. We observe long-range (~1 um) effects of membrane charge on protein mobility that extend well beyond classical Debye screening, which may reflect shape fluctuations of the GUV membrane. For the membrane-associated protein LactC2, we resolve two distinct diffusing populations within a single vesicle, corresponding to free and membrane-bound states. Our workflow provides a quantitative framework for probing single-protein mobility in vesicle-based synthetic cells. These results advance our understanding of how molecular crowding and transient membrane interactions shape protein diffusion within cell-sized compartments, with possible implications for metabolic organization.",
  "abstract_shown": true,
  "affiliations": [
    "University of Groningen"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 8,
  "authors": [
    {
      "name": "J. Coenradij"
    },
    {
      "name": "D. Linnik"
    },
    {
      "name": "K. Postmus"
    },
    {
      "name": "Z. Sensan"
    },
    {
      "name": "M. Accorsi"
    },
    {
      "name": "C. M. Punter"
    },
    {
      "name": "R. Dimova"
    },
    {
      "affs": [
        0
      ],
      "name": "B. Poolman"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/9bkw46jbzjx1g.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.10.21.760703",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.10.21.760703v1.full",
  "id": "9bkw46jbzjx1g",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.10.21.760703v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "biophysics"
    ],
    [
      "openalex",
      "1312|Lipid Membrane Structure and Behavior"
    ]
  ],
  "openalex": "W7223211691",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.10.21.760703v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-21",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/9bkw46jbzjx1g.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:29:14Z",
      "native_id": "10.64898/2026.10.21.760703",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.10.21.760703v1"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "biorxiv:biophysics",
      "subfield": "biophysics"
    }
  ],
  "title": "Single-protein diffusion in micrometer-size vesicles is governed by viscosity, surface charge, and membrane interactions",
  "title_text": "Single-protein diffusion in micrometer-size vesicles is governed by viscosity, surface charge, and membrane interactions",
  "type": "preprint",
  "updated_at": "2026-10-30T12:29:14Z",
  "url": "https://research.draconitic.com/paper/9bkw46jbzjx1g",
  "venue": "bioRxiv",
  "versions": []
}