Phosphoproteome analysis of the pathogenic bacterium Helicobacter pylori reveals over‐representation of tyrosine phosphorylation and multiply phosphorylated proteins

Abstract

Increasing evidence shows that protein phosphorylation on serine (Ser), threonine (Thr) and tyrosine (Tyr) residues is a major regulatory post-translational modification in the bacteria. To reveal the phosphorylation state in the Gram-negative pathogenic bacterium Helicobacter pylori, we carried out a global and site-specific phosphoproteomic analysis based on TiO(2) -phosphopeptide enrichment and high-accuracy LC-MS/MS determination. Eighty-two phosphopeptides from 67 proteins were identified with 126 phosphorylation sites, among which 79 class I sites were determined to have a distribution of 42.8:38.7:18.5% for the Ser/Thr/Tyr phosphorylation, respectively. The H. pylori phosphoproteome is characterized by comparably big size, high ratio of Tyr phosphorylation, high abundance of multiple phosphorylation sites in individual phosphopeptides and over-representation of membrane proteins. An interaction network covering 28 phosphoproteins was constructed with a total of 163 proteins centering on the major H. pylori virulence factor VacA, indicating that protein phosphorylation in H. pylori may be delicately controlled to regulate many aspects of the metabolic pathways and bacterial virulence.

Comparative Phosphoproteomics Reveals the Role of AmpC β-lactamase Phosphorylation in the Clinical Imipenem-resistant Strain Acinetobacter baumannii SK17

“…Nevertheless, our results were comparable to those reported for Mycobacterium tuberculosis which has a similar genome size (Table I) (27,34,(55)(56)(57)(58)(59)(60)(61)(62). Accordingly, the phosphoproteins identified from SK17-S accounted for 8.1% all open reading frames encoded in the genome of A. baumannii SK17 compared with 7.5% of M. tuberculosis (56,63).…”

Bacterial tyrosine kinases: evolution, biological function and structural insights

“…Upon examination of BYmediated protein phosphorylation sites, no clear-cut recognition motifs emerged in the immediate surroundings of the phosphorylated tyrosines. Moreover, if one considers the number of tyrosine-phosphorylation sites detected in recent phosphoproteomic studies (table 1), the conservation of phosphotyrosine sites is nearly non-existent [84,[91][92][93][94][95][96][97][98][99]. The existence of a specific phosphorylation motif is therefore unlikely in proteins phosphorylated by BY-kinases, and it seems likely that they recognize structural motifs distant from the phosphorylated tyrosine.…”

Global analysis of bacterial membrane proteins and their modifications

“…The knowledge of the existence of such PTMs could elucidate a better understanding of the function of bacterial membrane proteins. For example, a recent phosphoproteomic study in Helicobacter Pylori employed the TiO 2 enrichment strategy to perform a global site specific enrichment of Ser/Thr/Tyr phosphorylated proteins (Ge et al, 2011). To this end, authors found that many of these phosphorylation events were overrepresented in numerous membrane proteins, indicating that these proteins and their respective phosphorylation events could be an important mechanism in virulence control.…”