Identification of the Lactobacillus SLP domain that binds gastric mucin

Abstract

Surface layer proteins (SLPs) of lactobacillus bacteria have some structural regions responsible for adhesion to the intestinal epithelium. To identify the SLP and the smallest domain within the protein that is responsible for the adhesion of the bacterium to the intestinal epithelium, L. plantarum strain CGMCC1258 was investigated in this study. Using bioinformatics and molecular techniques, we first identified and purified a novel protein, integral membrane protein-2 (IMP-2, 33-45 kDa) responsible for adhesion to gastric mucin. Truncated forms of IMP-2 were then constructed and expressed, and the amino acids from 515 to 575 (designated micro IMP, MIMP) was identified as the smallest domain responsible for adhesion to gastric mucin. Competing assay was performed, which further confirmed the ability of MIMP to compete with enteroinvasive E. coli and enteropathogenic E. coli to adhere to cells of a normal colon cell line, NCM460. Furthermore, MIMP could maturate dendritic cells. These findings set a foundation for further investigation on the role of MIMP in the treatment and prevention of inflammation-related diseases of the intestine.

Involvement of the Mannose Receptor and p38 Mitogen-Activated Protein Kinase Signaling Pathway of the Microdomain of the Integral Membrane Protein after Enteropathogenic Escherichia coli Infection

“…As a result of larger protein fragments, an unclear domain, and an undefined mechanism, the disease resistance of SLP is still weak, and the clinical application of SLP is still limited. Our recent study showed that the SLP functional domain MIMP, which was responsible for adhesion to human IECs, could mediate the adherence of L. plantarum to IECs (28). Moreover, we further purified and successfully characterized the biological function of MIMP (27).…”

“…The intestinal epithelial monolayers were treated with EPEC for 24 h in the presence or absence of MIMP, as described previously (27,28). The EPEC strain ATCC 43887 (O111:NM; Shanghai Municipal Center for Disease Control and Prevention, Shanghai, China) was grown in static DMEM at 37°C for 24 h to allow intimate adherence and pedestal formation.…”

“…Recombinant MIMP was expressed in E. coli as described in our previous studies (27,28). Anti-MIMP antibodies were prepared by immunizing an adult male New Zealand White rabbit with MIMP.…”

Micro Integral Membrane Protein (MIMP), a Newly Discovered Anti-Inflammatory Protein of Lactobacillus Plantarum, Enhances the Gut Barrier and Modulates Microbiota and Inflammatory Cytokines

“…Recombinant MIMP was biosynthesized and identified as described in our previous study [12]. The DSS reagent was purchased from MP Biomedicals (USA).…”

“…Surprisingly, we found that SLP could significantly alleviate intestinal epithelial cells from enteropathogenic Escherichia coli (EPEC)-induced injury [11]. We further identified micro integral membrane protein (MIMP) as the smallest domain of SLPs and showed its role in the protection of intestinal epithelial cells from EPEC-induced injury [12-16]. …”