Open AccessMycoplasma pneumoniae CARDS Toxin Is Internalized via Clathrin-Mediated Endocytosis
Author(s) -
Manickam Krishnan,
Thirumalai R Kannan,
Joel B. Baseman
Publication year - 2013
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0062706
Subject(s) - internalization , endocytosis , mycoplasma pneumoniae , toxin , clathrin , microbiology and biotechnology , filipin , biology , diphtheria toxin , endosome , clostridium difficile toxin a , cell , biochemistry , intracellular , medicine , clostridium difficile , membrane , pneumonia , antibiotics
Bacterial toxins possess specific mechanisms of binding and uptake by mammalian cells. Mycoplasma pneumoniae CARDS (Community Acquired Respiratory Distress Syndrome) toxin is a 68 kDa protein, which demonstrates high binding affinity to human surfactant protein-A and exhibits specific biological activities including mono-ADP ribosylation and vacuolization. These properties lead to inflammatory processes in the airway and a range of cytopathologies including ciliostasis, loss of tissue integrity and injury, and cell death. However, the process by which CARDS toxin enters target cells is unknown. In this study, we show that CARDS toxin binds to mammalian cell surfaces and is internalized rapidly in a dose and time-dependent manner using a clathrin-mediated pathway, as indicated by inhibition of toxin internalization by monodansylcadaverine but not by methyl-β-cyclodextrin or filipin. Furthermore, the internalization of CARDS toxin was markedly inhibited in clathrin-depleted cells.