A Porphyromonas gingivalis haloacid dehalogenase family phosphatase interacts with human phosphoproteins and is important for invasion.

Haloacid dehalogenase (HAD) family phosphatases are widespread in prokaryotes and are generally involved in metabolic processes. Porphyromonas gingivalis, an invasive periodontal pathogen, secretes the HAD family phosphoserine phosphatase SerB653 when in contact with gingival epithelial cells. Here we characterize the structure and enzymatic activity of SerB653 and show that a SerB653 allelic replacement mutant of P. gingivalis is deficient in internalization and persistence in gingival epithelial cells. In contrast, mutation of a second HAD family serine phosphatase of P. gingivalis (SerB1170), or of a serine transporter, did not affect invasion. A pull-down assay identified GAPDH and heat-shock protein 90 as potential substrates for SerB653. Furthermore, exogenous phosphatase regulated microtubule dynamics in host cells. These data indicate that P. gingivalis has adapted a formerly metabolic enzyme to facilitate entry into host cells by modulating host cytoskeletal architecture. Our findings define a virulence-related role of a HAD family phosphatase and reveal an invasin of an important periodontal pathogen.