InterPro: IPR016667 Capsular polysaccharide synthesis, CpsB/CapC

Capsular polysaccharide biosynthesis proteins are critical for the production of a mature capsule in vitro. Members of Streptococcus pneumoniae have variable capsules, with about 90 known capsular serotypes that all have their own polysaccharide structure. cps14B to cps14H products are similar to other proteins involved in bacterial polysaccharide biosynthesis in both Gram-negative and -positive bacteria [1]. CpsA to cpsD are common to most serotypes. CpsD is an autophosphorylating protein-tyrosine kinase. CpsC is required for CpsD tyrosine-phosphorylation, and CpsB is required for dephosphorylation of CpsD. CpsB is a novel manganese-dependent phosphotyrosine-protein phosphatase that belongs to the PHP (polymerase and histidinol phosphatase) family of phosphoesterases [2]. Phosphorylation of proteins on hydroxyl amino acids (serine, threonine, tyrosine) occurs at different stages of pathenogenesis, including cell-cell interaction and adherence, translocation of bacterial effectors into host cells, and changes in host cellular structure and function induced by infection [3]. CpsB, CpsC, CpsD, and ATP form a stable complex that enhances capsule synthesis and acts to regulate it [4].