Catabolite Control Protein A (CcpA) Contributes to Virulence and Regulation of Sugar Metabolism in Streptococcus pneumoniae

Abstract

We characterized the role of catabolite control protein A (ccpA) in the physiology and virulence of Streptococcus pneumoniae. S. pneumoniae has a large percentage of its genome devoted to sugar uptake and metabolism, and therefore, regulation of these processes is likely to be crucial for fitness in the nasopharynx and may play a role during invasive disease. In many bacteria, carbon catabolite repression (CCR) is central to such regulation, influencing hierarchical sugar utilization and growth rates. CcpA is the major transcriptional regulator in CCR in several gram-positive bacteria. We show that CcpA functions in CCR of lactose-inducible ␤-galactosidase activity in S. pneumoniae. CCR of maltose-inducible ␣-glucosidase, raffinose-inducible ␣-galactosidase, and cellobiose-inducible ␤-glucosidase is unaffected in the ccpA strain, suggesting that other regulators, possibly redundant with CcpA, control these systems. The ccpA strain is severely attenuated for nasopharyngeal colonization and lung infection in the mouse, establishing its role in fitness on these mucosal surfaces. Comparison of the cell wall fraction of the ccpA and wild-type strains shows that CcpA regulates many proteins in this compartment that are involved in central and intermediary metabolism, a subset of which are required for survival and multiplication in vivo. Both in vitro and in vivo defects were complemented by providing ccpA in trans. Our results demonstrate that CcpA, though not a global regulator of CCR in S. pneumoniae, is required for colonization of the nasopharynx and survival and multiplication in the lung.Carbon metabolism and its regulation are central to prokaryotic life. Sugars serve as the most facile source of carbon and energy, both of which are needed to replenish essential nucleotide cofactors and other metabolites in the cell. When faced with a wide variety of carbon and energy sources, a bacterium has to make metabolic decisions, opting for preferential use of one source over another in order to maintain optimal growth (70, 74).

A fine scale phenotype–genotype virulence map of a bacterial pathogen

“…Single gene knockouts were constructed by replacing the coding sequence with a Cm or Spec resistance cassette as described previously (Iyer et al 2005;van Opijnen and Camilli 2010). Except for specific growth and selection experiments, S. pneumoniae was grown statically in Todd Hewitt broth supplemented with yeast extract (THY) and 5 mL/mL Oxyrase (Oxyrase, Inc) or on Sheep's blood agar plates at 37°C in a 5% CO 2 atmosphere.…”

Polyamine biosynthesis and transport mechanisms are crucial for fitness and pathogenesis of Streptococcus pneumoniae

“…This is of particular importance, as it spends most of its life cycle on nutritionally restricted mucosal surfaces, and the acquisition of scarce but essential nutrients represents a critical cellular function. Indeed, pneumococci possess multiple mechanisms for carbohydrate uptake and metabolism that are intricately linked to their pathogenesis (Iyer et al, 2005;Iyer & Camilli, 2007). Transport and biosynthesis of amino acids, manganese and iron have been shown to be important for pneumococcal pathogenesis (Basavanna et al, 2009;Gupta et al, 2009;Nanduri et al, 2008;Rosch et al, 2009;Yesilkaya et al, 2000).…”

“…However, in some cases it can cause pneumonia, septicaemia, otitis media and meningitis . Two capsular polysaccharide-based vaccines are currently licensed to prevent pneumococcal colonization and disease (Iyer et al, 2005;Iyer & Camilli, 2007). However, these vaccines are ineffective in reducing disease incidence in children and the elderly (Fedson, 1999;Huang et al, 2005).…”

A Novel Mode of Regulation of the Staphylococcus aureus Catabolite Control Protein A (CcpA) Mediated by Stk1 Protein Phosphorylation

“…The CcpA⅐Hpr-Ser(P)-46 complex has an increased affinity for particular cis-acting sequences, termed catabolite-responsive element (cre) sequences, and thereby represses or enhances gene expression depending on the position of the cre in relation to the operator sequence (3,4). In a number of Gram-positive pathogens such as Bacillus anthracis (5), Clostridium difficile (6), Staphylococcus aureus (7), Staphylococcus epidermidis (8), Streptococcus pneumoniae (9), and Streptococcus pyogenes (10), CcpA is also involved in the regulation of virulence determinants.…”