title: An antifungal protein from Ginkgo biloba binds actin and can trigger cell death.
abstract: Ginkbilobin is a short antifungal protein that had been purified and cloned from the seeds of the living fossil Ginkgo biloba. Homologues of this protein can be detected in all seed plants and the heterosporic fern Selaginella and are conserved with respect to domain structures, peptide motifs, and specific cysteine signatures. To get insight into the cellular functions of these conserved motifs, we expressed green fluorescent protein fusions of full-length and truncated ginkbilobin in tobacco BY-2 cells. We show that the signal peptide confers efficient secretion of ginkbilobin. When this signal peptide is either cleaved or masked, ginkbilobin binds and visualizes the actin cytoskeleton. This actin-binding activity of ginkbilobin is mediated by a specific subdomain just downstream of the signal peptide, and this subdomain can also coassemble with actin in vitro. Upon stable overexpression of this domain, we observe a specific delay in premitotic nuclear positioning indicative of a reduced dynamicity of actin. To elucidate the cellular response to the binding of this subdomain to actin, we use chemical engineering based on synthetic peptides comprising different parts of the actin-binding subdomain conjugated with the cell-penetrating peptide BP100 and with rhodamine B as a fluorescent reporter. Binding of this synthetic construct to actin efficiently induces programmed cell death. We discuss these findings in terms of a working model, where ginkbilobin can activate actin-dependent cell death.
authors: Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany.
authors: Ningning
authors: N
authors: Gao
authors: Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany.
authors: Parvesh
authors: P
authors: Wadhwani
authors: Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany.
authors: Philipp
authors: P
authors: Mühlhäuser
authors: Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany.
authors: Qiong
authors: Q
authors: Liu
authors: Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany.
authors: Michael
authors: M
authors: Riemann
authors: Institute for Biological Interfaces (IBG-2), KIT, P.O. Box 3640, 76021, Karlsruhe, Germany.|Institute of Organic Chemistry and CFN, KIT, Fritz-Haber-Weg 6, 76131, Karlsruhe, Germany.
authors: Anne S
authors: AS
authors: Ulrich
authors: Molecular Cell Biology, Botanical Institute and DFG-Center of Functional Nanostructures (CFN), Karlsruhe Institute of Technology (KIT), Kaiserstr. 2, 76128, Karlsruhe, Germany. peter.nick@kit.edu.
authors: Peter
authors: P
authors: Nick
mesh_terms: D000199:Actins / Q000737:chemistry; D000935:Antifungal Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D057846:Cell-Penetrating Peptides / Q000378:metabolism / Q000494:pharmacology; D020441:Ginkgo biloba / Q000737:chemistry / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D000072417:Protein Domains; D021381:Protein Transport; D014026:Nicotiana / Q000166:cytology
chemical_list: D000199:Actins; D000935:Antifungal Agents; D023181:Antimicrobial Cationic Peptides; D057846:Cell-Penetrating Peptides; D010940:Plant Proteins; C519081:ginkbilobin-2 protein, Ginkgo biloba
keywords: Actin; Antifungal protein; Cell-penetrating peptide; Programmed cell death