{
  "abstract": "Phosphoinositides are key regulators of membrane-associated signaling, yet their electrostatic properties are commonly represented by a single nominal charge in molecular simulations and structural models. Using the essential protein kinase AKT1 as a model system, we show that phosphoinositide protonation microstates, both the degree and positional placement of protons, govern peripheral membrane-protein recognition. By integrating quantum-mechanics-derived headgroup parameters, microsecond-scale all-atom molecular dynamics, and umbrella-sampling free-energy calculations with the available solid-state NMR-derived lipid populations via Bayesian/Maximum Entropy reweighting, we account explicitly for the thermodynamic ensemble of phosphoinositide proto-nation states. This population-weighted free-energy framework provides a quantitative mechanistic rationale for the strict specificity of wild-type AKT1 toward PI(3, 4, 5)P3 and elucidates how the oncogenic sentry mutation (E17K) alters this specificity to enable high-affinity PIP2 binding. Furthermore, Proximity-based Labeling of Membrane Associated Proteins (PLiMAP) assays experimentally confirm that AKT1 pleckstrin homology domain binding to distinct phosphoinositide species is differentially sensitive to pH. Together, our findings establish a direct connection between phosphoinositide protonation equilibria, binding energetics, and AKT1 lipid specificity. Beyond AKT1, these results demonstrate that the dynamic protonation microstates of anionic phospholipids act as a functional regulatory layer governing peripheral membrane-protein recruitment across diverse cellular microenvironments.",
  "abstract_shown": true,
  "affiliations": [
    "Indian Institute of Science"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "name": "K. Jha"
    },
    {
      "name": "M. Sarkar"
    },
    {
      "name": "K. Baratam"
    },
    {
      "name": "J. Nagesh"
    },
    {
      "name": "T. Pucadyil"
    },
    {
      "affs": [
        0
      ],
      "name": "A. Srivastava"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/90g1k2rnbpkez.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.05.749365",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.09.05.749365v1.full",
  "id": "90g1k2rnbpkez",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.09.05.749365v1",
  "language": null,
  "licence": "CC-BY-NC",
  "licence_label": "CC BY-NC",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by-nc/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "biorxiv",
      "biophysics"
    ],
    [
      "openalex",
      "1312|Lipid Membrane Structure and Behavior"
    ]
  ],
  "openalex": "W7212138959",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.09.05.749365v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-05",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/90g1k2rnbpkez.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:20:58Z",
      "native_id": "10.64898/2026.09.05.749365",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.09.05.749365v1"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "biorxiv:biophysics",
      "subfield": "biophysics"
    }
  ],
  "title": "Phosphoinositides protonation states dictate AKT1 binding with membrane",
  "title_text": "Phosphoinositides protonation states dictate AKT1 binding with membrane",
  "type": "preprint",
  "updated_at": "2026-10-30T12:20:58Z",
  "url": "https://research.draconitic.com/paper/90g1k2rnbpkez",
  "venue": "bioRxiv",
  "versions": []
}