The E1 beta-subunit of pyruvate dehydrogenase is surface-expressed in Lactobacillus plantarum and binds fibronectin.
Lactobacillus plantarum is among the species with a probiotic activity. Adhesion of probiotic bacteria to host tissues is an important principle for strain selection, because it represents a crucial step in the colonization process of either pathogens or commensals. Most bacterial adhesins are proteins, and a major target for them is fibronectin, an extracellular matrix glycoprotein. In this study we demonstrate that PDHB, a component of the pyruvate dehydrogenase complex, is a factor contributing to fibronectin-binding in L. plantarum LM3. By means of fibronectin overlay immunoblotting assay, we identified a L. plantarum LM3 surface protein with apparent molecular mass of 35 kDa. Mass spectrometric analysis shows that this protein is the pyruvate dehydrogenase E1 beta-subunit (PDHB). The corresponding pdhB gene is located in a 4-gene cluster encoding pyruvate dehydrogenase. In LM3-B1, carrying a null mutation in pdhB, the 35 kDa adhesin was not anymore detectable by immunoblotting assay. Nevertheless, the pdhB null mutation did not abolish pdhA, pdhC, and pdhD transcription in LM3-B1. By adhesion assays, we show that LM3-B1 cells bind to immobilized fibronectin less efficiently than wild type cells. Moreover, we show that pdhB expression is negatively regulated by the CcpA protein and is induced by bile.
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche, e Farmaceutiche, Seconda Università di Napoli, via Vivaldi 43, 81100 Caserta, Italy.
Valeria
V
Vastano
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche, e Farmaceutiche, Seconda Università di Napoli, via Vivaldi 43, 81100 Caserta, Italy.
Marzia
M
Salzillo
Centro di Spettrometria di Massa Proteomica e Biomolecolare, Istituto di Scienze dell'Alimentazione, CNR, Avellino, Italy.
Rosa A
RA
Siciliano
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche, e Farmaceutiche, Seconda Università di Napoli, via Vivaldi 43, 81100 Caserta, Italy.
Lidia
L
Muscariello
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche, e Farmaceutiche, Seconda Università di Napoli, via Vivaldi 43, 81100 Caserta, Italy.
Margherita
M
Sacco
Dipartimento di Scienze e Tecnologie Ambientali, Biologiche, e Farmaceutiche, Seconda Università di Napoli, via Vivaldi 43, 81100 Caserta, Italy. Electronic address: rosangela.marasco@unina2.it.
Rosangela
R
Marasco
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002473:Cell Wall / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D005353:Fibronectins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D048191:Lactiplantibacillus plantarum / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D030481:Pyruvate Dehydrogenase (Lipoamide) / Q000235:genetics* / Q000378:metabolism*
D001426:Bacterial Proteins; D005353:Fibronectins; D030481:Pyruvate Dehydrogenase (Lipoamide); C111305:pyruvate dehydrogenase E1 beta subunit
Adhesins; Fibronectin; Lactobacillus plantarum; PDHB; Probiotics