title: In cellulo phosphorylation induces pharmacological reprogramming of maurocalcin, a cell-penetrating venom peptide.
abstract: The venom peptide maurocalcin (MCa) is atypical among toxins because of its ability to rapidly translocate into cells and potently activate the intracellular calcium channel type 1 ryanodine receptor (RyR1). Therefore, MCa is potentially subjected to posttranslational modifications within recipient cells. Here, we report that MCa Thr(26) belongs to a consensus PKA phosphorylation site and can be phosphorylated by PKA both in vitro and after cell penetration in cellulo. Unexpectedly, phosphorylation converts MCa from positive to negative RyR1 allosteric modulator. Thr(26) phosphorylation leads to charge neutralization of Arg(24), a residue crucial for MCa agonist activity. The functional effect of Thr(26) phosphorylation is partially mimicked by aspartyl mutation. This represents the first case, to our knowledge, of both ex situ posttranslational modification and pharmacological reprogramming of a small natural cystine-rich peptide by target cells. So far, phosphorylated MCa is the first specific negative allosteric modulator of RyR1, to our knowledge, and represents a lead compound for further development of phosphatase-resistant analogs.
authors.affiliation: INSERM U836, LabEx Ion Channel, Science and Therapeutics, Grenoble Institute of Neuroscience, 38042 Grenoble, France; Université Grenoble Alpes, 38042 Grenoble, France; michel.dewaard@univ-nantes.fr michel.ronjat@ujf-grenoble.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: Ronjat
authors.affiliation: Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616;
authors.forename: Wei
authors.initials: W
authors.lastname: Feng
authors.affiliation: INSERM U836, LabEx Ion Channel, Science and Therapeutics, Grenoble Institute of Neuroscience, 38042 Grenoble, France; Université Grenoble Alpes, 38042 Grenoble, France;
authors.forename: Lucie
authors.initials: L
authors.lastname: Dardevet
authors.affiliation: Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616;
authors.forename: Yao
authors.initials: Y
authors.lastname: Dong
authors.affiliation: INSERM U836, LabEx Ion Channel, Science and Therapeutics, Grenoble Institute of Neuroscience, 38042 Grenoble, France; Université Grenoble Alpes, 38042 Grenoble, France;
authors.forename: Sawsan
authors.initials: S
authors.lastname: Al Khoury
authors.affiliation: CNRS UMR 7275, LabEx Ion Channel, Science and Therapeutics, Institut de Pharmacologie Moléculaire et Cellulaire, F-06560 Valbonne, France; Université de Nice Sophia Antipolis, F-06560 Nice, France;
authors.forename: Franck C
authors.initials: FC
authors.lastname: Chatelain
authors.affiliation: INSERM U836, LabEx Ion Channel, Science and Therapeutics, Grenoble Institute of Neuroscience, 38042 Grenoble, France; Université Grenoble Alpes, 38042 Grenoble, France; Smartox Biotechnologies, 38400 Saint-Martin d'Hères, France;
authors.forename: Virginie
authors.initials: V
authors.lastname: Vialla
authors.affiliation: INSERM U836, LabEx Ion Channel, Science and Therapeutics, Grenoble Institute of Neuroscience, 38042 Grenoble, France; Université Grenoble Alpes, 38042 Grenoble, France;
authors.forename: Samir
authors.initials: S
authors.lastname: Chahboun
authors.affiliation: CNRS UMR 7275, LabEx Ion Channel, Science and Therapeutics, Institut de Pharmacologie Moléculaire et Cellulaire, F-06560 Valbonne, France; Université de Nice Sophia Antipolis, F-06560 Nice, France;
authors.forename: Florian
authors.initials: F
authors.lastname: Lesage
authors.affiliation: Architecture et Fonction des Macromolécules Biologiques-CNRS UMR 7257, Aix-Marseille Université, 13009 Marseille, France.
authors.forename: Hervé
authors.initials: H
authors.lastname: Darbon
authors.affiliation: Department of Molecular Biosciences, School of Veterinary Medicine, University of California, Davis, CA 95616;
authors.forename: Isaac N
authors.initials: IN
authors.lastname: Pessah
authors.affiliation: INSERM U836, LabEx Ion Channel, Science and Therapeutics, Grenoble Institute of Neuroscience, 38042 Grenoble, France; Université Grenoble Alpes, 38042 Grenoble, France; Smartox Biotechnologies, 38400 Saint-Martin d'Hères, France; michel.dewaard@univ-nantes.fr michel.ronjat@ujf-grenoble.fr.
authors.forename: Michel
authors.initials: M
authors.lastname: De Waard
mesh_terms: D002118:Calcium / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism; D057809:HEK293 Cells; D006706:Homeostasis; D006801:Humans; D010766:Phosphorylation; D011499:Protein Processing, Post-Translational; D019837:Ryanodine Receptor Calcium Release Channel / Q000187:drug effects; D012604:Scorpion Venoms / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D019837:Ryanodine Receptor Calcium Release Channel; D012604:Scorpion Venoms; C406406:maurocalcine; D017868:Cyclic AMP-Dependent Protein Kinases; D002118:Calcium
keywords: maurocalcin; pharmacology; phosphorylation; ryanodine receptor; toxin