Paracoccidioides brasiliensis Enolase Is a Surface Protein That Binds Plasminogen and Mediates Interaction of Yeast Forms with Host Cells

Abstract

Paracoccidioidomycosis (PCM), caused by the dimorphic fungusParacoccidioides brasiliensis, is a disseminated, systemic disorder that involves the lungs and other organs. The ability of the pathogen to interact with host components, including extracellular matrix (ECM) proteins, is essential to further colonization, invasion, and growth. Previously, enolase (EC 4.2.1.11) was characterized as a fibronectin binding protein in P. brasiliensis. Interaction of surface-bound enolase with plasminogen has been incriminated in tissue invasion for pathogenesis in several pathogens. In this paper, enolase was expressed in Escherichia coli as a recombinant glutathione S-transferase (GST) fusion protein (recombinant P. brasiliensis enolase [rPbEno]). The P. brasiliensis native enolase (PbEno) was detected at the fungus surface and cytoplasm by immunofluorescence with an anti-rPbEno antibody. Immobilized purified rPbEno bound plasminogen in a specific, concentrationdependent fashion. Both native enolase and rPbEno activated conversion of plasminogen to plasmin through tissue plasminogen activator. The association between PbEno and plasminogen was lysine dependent. In competition experiments, purified rPbEno, in its soluble form, inhibited plasminogen binding to fixed P. brasiliensis, suggesting that this interaction required surface-localized PbEno. Plasminogen-coated P. brasiliensis yeast cells were capable of degrading purified fibronectin, providing in vitro evidence for the generation of active plasmin on the fungus surface. Exposure of epithelial cells and phagocytes to enolase was associated with an increased expression of surface sites of adhesion. In fact, the association of P. brasiliensis with epithelial cells and phagocytes was increased in the presence of rPbEno. The expression of PbEno was upregulated in yeast cells derived from mouse-infected tissues. These data indicate that surface-associated PbEno may contribute to the pathogenesis of P. brasiliensis.

A Surface Enolase Participates in Borrelia burgdorferi-Plasminogen Interaction and Contributes to Pathogen Survival within Feeding Ticks

“…In eukaryotes, however, certain scaffold proteins bind enolase through its PDZ domain and translocate the enzyme to the plasma membrane (24). Although the mechanism of enolase transport awaits further study, it is a well-known fact that many pathogens including Trichomonas vaginalis (33), Candida albicans (27), Paracoccidioides brasiliensis (34), or Streptococcus suis (18) transport enolase to the microbial surface, where it interacts with host Pg. The Pg-enolase interaction is mediated by two C-terminal lysine residues of enolase and highly conserved kringle domains of Pg (5).…”

“…Since enolase is one of the well-known Pg-binding proteins detected in many pathogenic organisms (18,27,33,34,37,38), we next assessed whether enolase is involved in B. burgdorferi-Pg interaction. To accomplish this, we used enolase antibodies and specific inhibitors, as extensively used in previous studies (18,22,23).…”

Characterization of pyruvate dehydrogenase subunit B and enolase as plasminogen-binding proteins in Mycoplasma pneumoniae

“…Using proteome analysis, PDHB was identified as an antigen that reacts with M. pneumoniae-positive patient sera (Nuyttens et al, 2010). The interaction of PDHB with plasminogen and the previously described binding to human fibronectin (Dallo et al, 2002) show that this molecule belongs to the group of proteins mediating contact to more than one ECM component, such as enolase of P. brasiliensis (Donofrio et al, 2009;Nogueira et al, 2010). To our knowledge, this is the first proof of an interaction of PDHB with human plasminogen.…”

Blood–brain barrier invasion by Cryptococcus neoformans is enhanced by functional interactions with plasmin

“…A potential role for the plasminogen fibrinolytic network in the virulence of invasive fungal pathogens is underscored by the increasing number of medically important fungi that bind plasminogen, including Candida albicans (Crowe et al, 2003;Jong et al, 2003), Paracoccidioides brasiliensis (Nogueira et al, 2010), Aspergillus fumigatus (Zaas et al, 2008), Pneumocystis jiroveci (carinii) (Fox & Smulian, 2001) and C. neoformans (Stie et al, 2009). This interaction confers or supplements the ability of fungi to degrade physiological substrate (Nogueira et al, 2010;Stie et al, 2009) and enhances Candida albicans invasion of BMEC, in vitro .…”

“…This interaction confers or supplements the ability of fungi to degrade physiological substrate (Nogueira et al, 2010;Stie et al, 2009) and enhances Candida albicans invasion of BMEC, in vitro . In light of the strong affinity of blood-borne C. neoformans for the CNS, an important but unresolved question is whether plasminogen deposition contributes to cryptococcal invasion of the highly restrictive BMEC component of the BBB.…”