Lipid raft-associated
clathrin is essential for host-pathogen interactions during
infection. Brucella abortus is an intracellular pathogen that circumvents host defenses, but little is known about the precise
infection mechanisms that involve interaction with
lipid raft-associated mediators. The aim of this study was to elucidate the
clathrin-mediated phagocytic mechanisms of B. abortus. The
clathrin dependence of B. abortus
infection in HeLa cells was investigated using an
infection assay and immunofluorescence microscopy. The redistribution of
clathrin in the membrane and in phagosomes was investigated using
sucrose gradient fractionation of
lipid rafts and the isolation of B. abortus-containing vacuoles, respectively.
Clathrin and
dynamin were concentrated into
lipid rafts during B. abortus
infection, and the entry and intracellular survival of B. abortus within HeLa cells were abrogated by
clathrin inhibition.
Clathrin disruption decreased actin polymerization and the colocalization of B. abortus-containing vacuoles with
clathrin and Rab5 but not
lysosome-associated membrane protein 1 (LAMP-1). Thus, our data demonstrate that
clathrin plays a fundamental role in the entry and intracellular survival of B. abortus via interaction with
lipid rafts and actin rearrangement. This process facilitates the early intracellular trafficking of B. abortus to safe replicative vacuoles.