IlsA, A Unique Surface Protein of Bacillus cereus Required for Iron Acquisition from Heme, Hemoglobin and Ferritin

PLoS Pathogens

Michel Gohar¹  Nadine Daou¹  Christina Nielsen-LeRoux¹  Jasmina Vidic¹  Hélène Bierne²  Didier Lereclus³  Christophe Buisson³  Mireille Kallassy⁴ 

[1] INRA-UR1249 Génétique Microbienne et Environnement, La Minière, Guyancourt, France;INRA-UR892 Unité de Biologie Physico-Chimique des Prions, Virologie et Immunologie Moléculaires, Jouy en Josas, France;Laboratoire de Biotechnologie, Université Saint-Joseph, Beyrouth, Lebanon;Unité Interaction Bactéries Cellules, Institut Pasteur, INSERM U604 – INRA USC2020, Paris, France

关键词: Bacillus cereus;    Ferritin;    Hemoglobin;    Heme;    Larvae;    Mutant strains;    Insects;    Bacillus anthracis;   

DOI  :  10.1371/journal.ppat.1000675

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

The human opportunistic pathogen Bacillus cereus belongs to the B. cereus group that includes bacteria with a broad host spectrum. The ability of these bacteria to colonize diverse hosts is reliant on the presence of adaptation factors. Previously, an IVET strategy led to the identification of a novel B. cereus protein (IlsA, Iron-regulated leucine rich surface protein), which is specifically expressed in the insect host or under iron restrictive conditions in vitro. Here, we show that IlsA is localized on the surface of B. cereus and hence has the potential to interact with host proteins. We report that B. cereus uses hemoglobin, heme and ferritin, but not transferrin and lactoferrin. In addition, affinity tests revealed that IlsA interacts with both hemoglobin and ferritin. Furthermore, IlsA directly binds heme probably through the NEAT domain. Inactivation of ilsA drastically decreases the ability of B. cereus to grow in the presence of hemoglobin, heme and ferritin, indicating that IlsA is essential for iron acquisition from these iron sources. In addition, the ilsA mutant displays a reduction in growth and virulence in an insect model. Hence, our results indicate that IlsA is a key factor within a new iron acquisition system, playing an important role in the general virulence strategy adapted by B. cereus to colonize susceptible hosts.

【 授权许可】

CC BY