Related Experiment Video
Updated: Jul 15, 2026

Enriching Subcellular Proteins in Leptospira Using a Triton X-114-Based Fractionation Approach
Published on: August 8, 2025
The surface protease PgtE of Salmonella enterica affects complement activity by proteolytically cleaving C3b, C4b and
Päivi Ramu1, Rauna Tanskanen, Mikko Holmberg
1Department of Biological and Environmental Sciences, University of Helsinki, Viikinkaari 9c, P.O. Box 56 FIN-00014, 00014 Helsinki, Finland. paivi.ramu@helsinki.fi <paivi.ramu@helsinki.fi>
Abstract:
Complement activity in mammalian serum is fundamentally based on three homologous components C3b, C4b and C5. During systemic infection, the gastrointestinal pathogen Salmonella enterica disseminates within host phagocytic cells but also extracellularly. Consequently, systemic Salmonella transiently confronts the complement system. We show here that the surface protease PgtE of S. enterica proteolytically cleaves C3b, C4b and C5 and that the expression of PgtE enhances bacterial resistance to human serum. Degradation of C3b was further enhanced by PgtE-mediated plasminogen activation.
Related Concept Videos
Complement System
Determinants of Bacterial Pathogenicity and Virulence
Regulation of Bacterial Virulence
Bacterial Gastroenteritis
The Proteasome
In this pathway, the target proteins are first tagged with small proteins called ubiquitin. A series of enzymes carry out the ubiquitination of the target proteins - E1 (ubiquitin-activating enzyme), E2 (ubiquitin-conjugating enzyme), and E3...
Antimicrobial Proteins
Interferons
Interferons (IFNs) are proteins produced by lymphocytes, macrophages, and fibroblasts infected with viruses. While IFNs cannot prevent viruses from entering and...

