Comparative Phosphoproteomics of Classical Bordetellae Elucidates the Potential Role of Serine, Threonine and Tyrosine Phosphorylation in Biology and Virulence.

The genus is divided into two groups: classical and non-classical. , and are known as classical bordetellae, a group of important human pathogens causing whooping cough or whooping cough-like disease and hypothesized to have evolved from environmental non-classical bordetellae. infections have increased globally driving the need to better understand these pathogens for the development of new treatments and vaccines. One unexplored component in is the role of serine, threonine and tyrosine phosphorylation. Therefore, this study characterized the phosphoproteome of classical bordetellae and examined its potential role in biology and virulence. Applying strict identification of localization criteria, this study identified 70 unique phosphorylated proteins in the classical group with a high degree of conservation. Phosphorylation was a key regulator of metabolism with proteins involved in gluconeogenesis, TCA cycle, amino acid and nucleotide synthesis significantly enriched. Three key virulence pathways were also phosphorylated including type III secretion system, alcaligin synthesis and the BvgAS master transcriptional regulatory system for virulence genes in . Seven new phosphosites were identified in BvgA with 6 located in the DNA binding domain. Of the 7, 4 were not present in non-classical bordetellae. This suggests that serine/threonine phosphorylation may play an important role in stabilizing/destabilizing BvgA binding to DNA for fine-tuning of virulence gene expression and that BvgA phosphorylation may be an important factor separating classical from non-classical bordetellae. This study provides the first insight into the phosphoproteome of classical species and the role that Ser/Thr/Tyr phosphorylation may play in biology and virulence.