The Diverse Roles of the Histone-Like Nucleoid Structuring (H-NS) Protein in Vibrio parahaemolyticus

The histone-like nucleoid structuring (H-NS) protein is a global transcriptional regulator critical for bacterial genome organization and gene expression. In Vibrio parahaemolyticus, H-NS represses virulence factors such as thermostable direct hemolysin (TDH), type III secretion systems (T3SS1/T3SS2), and type VI secretion systems (T6SS1/T6SS2). It also modulates swimming motility by activating polar flagellar genes while repressing swarming motility and lateral flagellar systems. Additionally, H-NS influences biofilm formation through regulation of exopolysaccharide synthesis and cyclic di-GMP (c-di-GMP) metabolism. Emerging evidence suggests cross-regulation with quorum sensing (QS) systems, though direct mechanistic insights into V. parahaemolyticus remain sparse. Furthermore, a recent study indicates H-NS roles extend to osmotic stress adaptation, such as regulating the ectoine biosynthetic pathway. This review synthesizes current knowledge on H-NS-mediated regulation in V. parahaemolyticus and offers new insights for future research.