{ "abstract": "The cation channel of sperm, CatSper, is a sperm-specific calcium channel essential for male fertility across metazoans. CatSper is activated by intracellular alkalinization, membrane depolarization, and elevated temperature, which together ensure maximal current generation. However, the structural mechanisms by which these physiological stimuli jointly regulate channel activation remain poorly understood, in part because CatSper is an unusually complex ~15-subunit assembly organized in zigzag supramolecular arrays along the sperm flagellum. Here, we combine comparative genomics across 47 species with AlphaFold3-based modeling and evolutionary sequence-structure analyses to investigate a mechanism underlying temperature and pH sensitivity of CatSper. Phylogenetic analysis shows that N-terminal length and histidine enrichment of the pore-forming subunit CatSper1 strongly correlate with species-specific fertilization temperatures, suggesting evolutionary adaptation of temperature and pH sensitivity. Structural modeling further revealed conserved surface-exposed histidine clusters that form predicted contact interfaces between adjacent CatSper assemblies, with this contact interface positioned near the dominant voltage-sensing module. Functional validation using electrophysiology and calcium imaging in mouse sperm shows that capacitation-associated partial removal of the CatSper1 N-terminus selectively impairs temperature-dependent activation. Together, these findings support a model in which temperature-dependent histidine deprotonation functionally couples neighboring CatSper complexes within the supramolecular assembly, thereby promoting synchronized channel activation.\n\nCatSper is a sperm-specific calcium channel essential for male fertility that is activated by changes in pH and temperature, but how these signals are integrated remains unclear. This study provides evidence suggesting that temperature-dependent histidine deprotonation within the CatSper1 N-terminus promotes neighboring complex coupling and activation.", "abstract_shown": true, "affiliations": [ "Department of Cell Biology and Physiology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America.", "Center for the Investigation of Membrane Excitability Diseases (CIMED), Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America.", "Department of Obstetrics and Gynecology, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America.", "Department of Biomedical Engineering and Center for Biomolecular Condensates, McKelvey School of Engineering, Washington University in St. Louis, St. Louis, Missouri, United States of America.", "BJC Investigator Program, Washington University School of Medicine in St. Louis, St. Louis, Missouri, United States of America." ], "article_type": "Discovery Report", "arxiv": null, "author_total": 9, "authors": [ { "affs": [ 0, 1 ], "name": "Billy Zhao" }, { "affs": [ 2 ], "name": "Shweta Bhagwat" }, { "affs": [ 2 ], "name": "Juan Ferreira" }, { "affs": [ 3 ], "name": "Kiersten M Ruff" }, { "affs": [ 0, 1 ], "name": "Dilip K Swain" }, { "affs": [ 3 ], "name": "Rohit V Pappu" }, { "affs": [ 2 ], "name": "Celia M Santi" }, { "affs": [ 0, 1 ], "name": "Ziao Fu", "orcid": "0000-0001-5036-1945" }, { "affs": [ 0, 1, 4 ], "name": "Polina V Lishko", "orcid": "0000-0003-3140-2769" } ], "bibtex": "https://research.draconitic.com/paper/16e4dcdr2kvw2.bib", "cited_by": 0, "doi": "10.1371/journal.pbio.3003776", "fulltext_url": "https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003776", "id": "16e4dcdr2kvw2", "issns": [ "1545-7885", "1544-9173" ], "landing_url": "https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003776", "language": "eng", "licence": "CC-BY", "licence_label": "CC BY", "licence_source": "article", "licence_url": "https://creativecommons.org/licenses/by/4.0/", "metadata_licence": null, "native_subjects": [ [ "openalex", "1312|Ion channel regulation and function" ], [ "plos", "/Biology and life sciences/Agriculture/Agrochemicals/Fertilizers" ], [ "plos", "/Biology and life sciences/Biochemistry/Proteins/Amino acids/Basic amino acids/Histidine" ], [ "plos", "/Biology and life sciences/Biochemistry/Proteins/Ion channels/Voltage-gated ion channels/Catsper channels" ], [ "plos", "/Biology and life sciences/Biophysics/Ion channels/Voltage-gated ion channels/Catsper channels" ], [ "plos", "/Biology and life sciences/Cell biology/Cellular types/Animal cells/Germ cells/Sperm" ], [ "plos", "/Biology and life sciences/Developmental biology/Fertilization" ], [ "plos", "/Biology and life sciences/Neuroscience/Neurophysiology/Ion channels/Voltage-gated ion channels/Catsper channels" ], [ "plos", "/Biology and life sciences/Physiology/Electrophysiology/Ion channels/Voltage-gated ion channels/Catsper channels" ], [ "plos", "/Biology and life sciences/Physiology/Electrophysiology/Neurophysiology/Ion channels/Voltage-gated ion channels/Catsper channels" ], [ "plos", "/Biology and life sciences/Physiology/Physiological parameters/Body temperature" ], [ "plos", "/Physical sciences/Chemistry/Chemical compounds/Organic compounds/Amino acids/Basic amino acids/Histidine" ], [ "plos", "/Physical sciences/Chemistry/Organic chemistry/Organic compounds/Amino acids/Basic amino acids/Histidine" ], [ "plos", "/Physical sciences/Physics/Biophysics/Ion channels/Voltage-gated ion channels/Catsper channels" ], [ "plos", "/Research and analysis methods/Database and informatics methods/Bioinformatics/Sequence analysis/Sequence alignment" ], [ "plos", "/Social sciences/Linguistics/Grammar" ] ], "openalex": "W7221117438", "pdf_url": "https://journals.plos.org/plosbiology/article/file?id=10.1371/journal.pbio.3003776&type=printable", "pmcid": "PMC13674862", "pmid": "42853877", "published": "2026-10-09", "publisher": "Public Library of Science", "ris": "https://research.draconitic.com/paper/16e4dcdr2kvw2.ris", "sources": [ { "first_seen": "2026-10-30T12:17:30Z", "native_id": "10.1371/journal.pbio.3003776", "source": "plos", "url": "https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3003776" }, { "first_seen": "2026-10-30T12:18:12Z", "native_id": "MED:42853877", "source": "europepmc", "url": "https://europepmc.org/article/MED/42853877" } ], "subjects": [ { "field": "biochemistry", "origin": "plos:biophysics", "subfield": "biophysics" }, { "field": "medicine", "origin": "plos:physiology", "subfield": "physiology" } ], "title": "A histidine-mediated supramolecular mechanism links temperature and pH activation of the sperm channel CatSper", "title_text": "A histidine-mediated supramolecular mechanism links temperature and pH activation of the sperm channel CatSper", "type": "peer-reviewed", "updated_at": "2026-10-30T12:18:12Z", "url": "https://research.draconitic.com/paper/16e4dcdr2kvw2", "venue": "PLOS Biology", "versions": [] }