Related Experiment Video
Updated: Apr 29, 2026

Super-Resolution Imaging of Bacterial Secreted Proteins Using Genetic Code Expansion
Published on: February 10, 2023
Global impact of Salmonella type III secretion effector SteA on host cells
Elena Cardenal-Muñoz1, Gabriel Gutiérrez1, Francisco Ramos-Morales1
1Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Apartado 1095, 41080 Sevilla, Spain.
Abstract:
Salmonella enterica is a Gram-negative bacterium that causes gastroenteritis, bacteremia and typhoid fever in several animal species including humans. Its virulence is greatly dependent on two type III secretion systems, encoded in pathogenicity islands 1 and 2. These systems translocate proteins called effectors into eukaryotic host cell. Effectors interfere with host signal transduction pathways to allow the internalization of pathogens and their survival and proliferation inside vacuoles. SteA is one of the few Salmonella effectors that are substrates of both type III secretion systems. Here, we used gene arrays and bioinformatics analysis to study the genetic response of human epithelial cells to SteA. We found that constitutive synthesis of SteA in HeLa cells leads to induction of genes related to extracellular matrix organization and regulation of cell proliferation and serine/threonine kinase signaling pathways. SteA also causes repression of genes related to immune processes and regulation of purine nucleotide synthesis and pathway-restricted SMAD protein phosphorylation. In addition, a cell biology approach revealed that epithelial cells expressing steA show altered cell morphology, and decreased cytotoxicity, cell-cell adhesion and migration.
Related Concept Videos
Bacterial Gastroenteritis
Gram-negative Bacterial Protein Secretion Systems
Stringent Response in E. coli
Bacterial Translocation and Protein Secretion
Other Stress Responses in Bacteria
Regulation of Bacterial Virulence

