Evidence map›Paper›PMID 42533721›Full record

ArticleMolecular reproduction and development2026

Mussel Spermatozoa Express a Specific Isoform of the Catalytic Subunit of cAMP-Dependent Protein Kinase.

Izaskun Ibarguren, Saskia-Camille Flament-Simon, Ana P Losada, Susana B Bravo, José Antonio Villamarín

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Article in Molecular reproduction and development, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

5 authors.

Izaskun IbargurenDepartment of Biochemistry and Molecular Biology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain.
Saskia-Camille Flament-SimonDepartment of Biochemistry and Molecular Biology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain.
Ana P LosadaDepartment of Veterinary Clinical Sciences, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain.
Susana B BravoProteomic Unit, Health Research Institute of Santiago de Compostela (IDIS), University Hospital of Santiago de Compostela, Santiago de Compostela, Spain.
José Antonio VillamarínDepartment of Biochemistry and Molecular Biology, Faculty of Veterinary, University of Santiago de Compostela, Lugo, Spain.

Funding

University of Santiago de Compostela and the Xunta de Galicia
6 · The paper itself

Abstract

cAMP-dependent protein kinase (PKA) plays a central role in regulating sperm motility in both invertebrates and mammals. The sea mussel Mytilus galloprovincialis provides a valuable model for investigating the molecular mechanisms underlying gamete activation in externally fertilizing organisms. In previous work, several catalytic (C) subunit isoforms of PKA were isolated from this species. Here, we report that one of these isoforms appears to be specifically expressed in spermatozoa, indicating the presence of a sperm-specific C-subunit isoform in a non-mammalian species. The protein was purified from male gonadal tissue and identified by LC-MS/MS as the isoform corresponding to UniProt entry A0A8B6GIP6. Sequence analysis revealed that this mussel C-isoform shares strong homology with mammalian sperm-specific Cα2-isoform within the catalytic core but possesses a unique N-terminal region. Whereas mammalian Cα2 contains a short six-residue N-terminal extension, the mussel sperm isoform features a longer acidic extension of 17 amino acids. Moreover, phosphoproteomic analysis reveals the presence of two phosphorylation sites (Ser5 and Thr30) in the N-terminal tail of the mussel C-subunit that are absent in Cα2. These structural differences suggest specific regulatory mechanisms associated with sperm activation in externally fertilizing bivalves. Immunolocalization studies show that the mussel sperm C-subunit is distributed in the acrosomal region, mitochondria, and along the flagellum, where it is predominantly associated with R

Indexed as

Cyclic AMP-Dependent Protein Kinase Catalytic SubunitsCyclic AMP-Dependent Protein KinasesMytilusSpermatozoaAmino Acid SequenceAnimalsCatalytic DomainIsoenzymesMaleMolecular Sequence DataPhosphorylationSperm ProteinsTandem Mass SpectrometryCyclic AMP-Dependent Protein Kinase Catalytic SubunitsCyclic AMP-Dependent Protein KinasesIsoenzymesSperm ProteinscAMP‐dependent protein kinaseC‐subunitLC‐MS/MSMytilusPKAsperm

Identifiers

PMID42533721
PMCPMC13425070

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.