Iron Delivery through Membrane Vesicles in Corynebacterium glutamicum
Kayuki Kawashima, Toshiki Nagakubo, Nobuhiko Nomura, Masanori Toyofuku
Abstract
Iron is an essential element of life. Many bacteria have developed iron acquisition systems, such as siderophores, for external iron uptake. Corynebacterium glutamicum, a soil bacterium known for its potential for industrial applications, was shown to lack the ability to produce extracellular, low-molecular-weight iron carriers, and it remains elusive how this bacterium acquires iron. Here, we demonstrated that MVs released from C. glutamicum cells could act as extracellular iron carriers that mediate iron uptake. Although MV-associated proteins or siderophores have been shown to play critical roles in MV-mediated iron uptake by other mycobacterial species, the iron delivery through C. glutamicum MVs is not dependent on these factors. Moreover, our results suggest that there is an unidentified mechanism that determines the species specificity of MV-mediated iron acquisition. Our results further demonstrated the important role of MV-associated iron.