{
  "abstract": "Voltage-gated Kv7 (KCNQ, M-type) potassium channels regulate cellular excitability through interactions with phosphatidylinositol 4,5-bisphosphate (PIP2;) and calmodulin (CaM). The distal B helix of Kv7.2-5 channels contains a conserved protein kinase C (PKC) phosphorylation site, suggesting that phosphorylation may regulate channel activity by altering CaM- and PIP2;-dependent mechanisms. Here, we investigated the effects of phosphorylation of Thr552 within the Kv7.4 B helix using electrophysiology, biophysical assays, NMR spectroscopy, and molecular dynamics simulations. Phosphomimetic substitution of Thr552 produced a loss-of-function phenotype characterized by reduced current density and a depolarizing shift in voltage-dependent activation without altering channel surface expression. Biophysical studies demonstrated that phosphorylation produced only modest effects on overall CaM association. However, NMR spectroscopy revealed phosphorylation-dependent changes in apoCaM interactions, and molecular dynamics simulations identified remodeling of the local interaction network surrounding the distal B-helix polybasic (KRK motif) region. In contrast, phosphorylation markedly reduced PIP2; binding to both the isolated B helix and CaM-associated Kv7.4 regulatory complexes. Mutation of the distal B-helix KRK motif similarly impaired PIP2; binding, identifying this region as an important determinant of lipid recognition. Together, these findings support a model in which phosphorylation of Thr552 suppresses Kv7.4 activity primarily by reducing PIP2; interactions while reorganizing, rather than disrupting, CaM binding. These results identify Thr552 as a critical regulatory site linking phosphorylation-dependent signaling to Kv7.4 channel gating.",
  "abstract_shown": true,
  "affiliations": [
    "University of Arkansas"
  ],
  "article_type": "New results",
  "arxiv": null,
  "author_total": 6,
  "authors": [
    {
      "name": "P. Phan"
    },
    {
      "name": "C. Okose"
    },
    {
      "name": "D. Sapkota"
    },
    {
      "name": "W. Munyao"
    },
    {
      "name": "D. Girodat"
    },
    {
      "affs": [
        0
      ],
      "name": "C. Archer"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/5xd65dzpqnk2s.bib",
  "cited_by": 0,
  "doi": "10.64898/2026.09.18.752758",
  "fulltext_url": "https://www.biorxiv.org/content/10.64898/2026.09.18.752758v1.full",
  "id": "5xd65dzpqnk2s",
  "issns": [],
  "landing_url": "https://www.biorxiv.org/content/10.64898/2026.09.18.752758v1",
  "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",
      "biochemistry"
    ],
    [
      "openalex",
      "1312|Ion channel regulation and function"
    ]
  ],
  "openalex": "W7214054710",
  "pdf_url": "https://www.biorxiv.org/content/10.64898/2026.09.18.752758v1.full.pdf",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-18",
  "publisher": null,
  "ris": "https://research.draconitic.com/paper/5xd65dzpqnk2s.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:23:47Z",
      "native_id": "10.64898/2026.09.18.752758",
      "source": "biorxiv",
      "url": "https://www.biorxiv.org/content/10.64898/2026.09.18.752758v1"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "openalex:1312|Ion channel regulation and function",
      "subfield": "molecular-biology"
    }
  ],
  "title": "Phosphorylation of the Kv7.4 B helix reorganizes calmodulin interactions and reduces PIP2 binding",
  "title_text": "Phosphorylation of the Kv7.4 B helix reorganizes calmodulin interactions and reduces PIP2 binding",
  "type": "preprint",
  "updated_at": "2026-10-30T12:23:47Z",
  "url": "https://research.draconitic.com/paper/5xd65dzpqnk2s",
  "venue": "bioRxiv",
  "versions": []
}