Uptake of Marasmius oreades agglutinin disrupts integrin-dependent cell adhesion

• Published in: Biochimica et biophysica acta Vol. 1860; no. 2; pp. 392 - 401
• Main Authors: Juillot, Samuel, Cott, Catherine, Madl, Josef, Claudinon, Julie, van der Velden, Niels Sebastiaan Johannes, Künzler, Markus, Thuenauer, Roland, Römer, Winfried
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.02.2016; Elsevier Pub. Co
• Subjects: agglutinins; Agglutinins - physiology; Animals; calpain; carbohydrate binding; carbohydrates; CD29 antigen; Cell Adhesion; cell death; cell viability; Cells, Cultured; Clathrin - physiology; Cysteine protease; cytoskeleton; dimerization; Dogs; Dynamins - physiology; Endocytosis; Endosomes - metabolism; enzyme activity; fluorescent antibody technique; Focal adhesion kinase; Focal Adhesion Protein-Tyrosine Kinases - physiology; fruiting bodies; image analysis; Integrin; Integrin beta1 - physiology; Lectin; lectins; Marasmius; Marasmius - chemistry; mushrooms; parasites; phosphorylation; predators; protective effect; toxicity; Western blotting; Lectin; PFA; FACS; RIPA; PNPG; DMEM; BSA; Tf; Integrin; Cell adhesion; CME; MDCKII; wt; MOA; PBS; HUS; StxB; ER; ECM; FAK; GSLs; PMP; Cysteine protease; PEI; FCS; BAX; HBSS; Focal adhesion kinase
• ISSN: 0304-4165; 0006-3002; 1872-8006
• DOI: 10.1016/j.bbagen.2015.11.002

Fruiting body lectins have been proposed to act as effector proteins in the defense of fungi against parasites and predators. The Marasmius oreades agglutinin (MOA) is a lectin from the fairy ring mushroom with specificity for Galα1-3Gal containing carbohydrates. This lectin is composed of an N-terminal carbohydrate-binding domain and a C-terminal dimerization domain. The dimerization domain of MOA shows in addition calcium-dependent cysteine protease activity, similar to the calpain family. Cell detachment assay, cell viability assay, immunofluorescence, live cell imaging and Western blot using MDCKII cell line. In this study, we demonstrate in MDCKII cells that after internalization, MOA protease activity induces profound physiological cellular responses, like cytoskeleton rearrangement, cell detachment and cell death. These changes are preceded by a decrease in FAK phosphorylation and an internalization and degradation of β1-integrin, consistent with a disruption of integrin-dependent cell adhesion signaling. Once internalized, MOA accumulates in late endosomal compartments. Our results suggest a possible toxic mechanism of MOA, which consists of disturbing the cell adhesion and the cell viability. After being ingested by a predator, MOA might exert a protective role by diminishing host cell integrity. •We studied MOA toxicity in MDCKII cells.•MOA disturbs integrin-dependent cell adhesion signaling.•Toxicity of the lectin is both binding- and protease-dependent.•MOA accumulates in late endosomal compartments.