Related Experiment Video
Updated: May 28, 2026

A Fluorescence-based Method to Study Bacterial Gene Regulation in Infected Tissues
Published on: February 19, 2019
The eukaryotic-type serine/threonine protein kinase Stk is required for biofilm formation and virulence in
Qian Liu1, Jiajia Fan, Chen Niu
1Key Laboratory of Medical Molecular Virology, Institutes of Biomedical Sciences, Fudan University, Shanghai, People's Republic of China.
Background:
Serine/threonine kinases are involved in gene regulation and signal transduction in prokaryotes and eukaryotes. Here, we investigated the role of the serine/threonine kinase Stk in the opportunistic pathogen Staphylococcus epidermidis.
Methodology/Principal Findings:
We constructed an isogenic stk mutant of a biofilm-forming clinical S. epidermidis isolate. Presence of stk was important for biofilm formation in vitro and virulence in a murine subcutaneous foreign body infection model. Furthermore, the stk mutant exhibited phenotypes indicating an impact of stk on metabolic pathways. Using different constructs for the genetic complementation of the stk mutant strain with full-length Stk or specific Stk domains, we determined that the Stk intracellular kinase domain is important for biofilm formation and regulation of purine metabolism. Site-specific inactivation of the Stk kinase domain led to defective biofilm formation, in further support of the notion that the kinase activity of Stk regulates biofilm formation of S. epidermidis. According to immunological detection of the biofilm exopolysaccharide PIA and real-time PCR of the PIA biosynthesis genes, the impact of stk on biofilm formation is mediated, at least in part, by a strong influence on PIA expression.
Conclusions:
Our study identifies Stk as an important regulator of biofilm formation and virulence of S. epidermidis, with additional involvement in purine metabolism and the bacterial stress response.
Related Concept Videos
Staphylococcal Skin Infections
Bacterial Gastroenteritis
Determinants of Bacterial Pathogenicity and Virulence
Regulation of Bacterial Virulence
Cytoskeletal Proteins in Bacteria
Gram-negative Bacterial Protein Secretion Systems

