Role of CcpA in Regulation of the Central Pathways of Carbon Catabolism in Bacillus subtilis

Abstract

The Bacillus subtilis two-dimensional (2D) protein index contains almost all glycolytic and tricarboxylic acid (TCA) cycle enzymes, among them the most abundant housekeeping proteins of growing cells. Therefore, a comprehensive study on the regulation of glycolysis and the TCA cycle was initiated. Whereas expression of genes encoding the upper and lower parts of glycolysis (pgi,pfk, fbaA, and pykA) is not affected by the glucose supply, there is an activation of the glycolytic gap gene and the pgk operon by glucose. This activation seems to be dependent on the global regulator CcpA, as shown by 2D polyacrylamide gel electrophoresis analysis as well as by transcriptional analysis. Furthermore, a high glucose concentration stimulates production and excretion of organic acids (overflow metabolism) in the wild type but not in the ccpAmutant. Finally, CcpA is involved in strong glucose repression of almost all TCA cycle genes. In addition to TCA cycle and glycolytic enzymes, the levels of many other proteins are affected by theccpA mutation. Our data suggest (i) that ccpAmutants are unable to activate glycolysis or carbon overflow metabolism and (ii) that CcpA might be a key regulator molecule, controlling a superregulon of glucose catabolism.

Regulation of the central glycolytic genes in Bacillus subtilis: binding of the repressor CggR to its single DNA target sequence is modulated by fructose‐1,6‐bisphosphate

“…The transcription of the gapA operon is derepressed when a glycolytically metabolizable carbohydrate is present in the culture medium (Tobisch et al, 1999;Fillinger et al, 2000). Ludwig et al (2001) have shown that the level of derepression varies depending on the carbohydrate, but that either carbohydrates catabolized via the upper part of glycolysis, such as glucose, glucitol, fructose or glycerol, or carbohydrates catabolized via the pentose phosphate pathway, such as gluconate or arabinose, did induce the gapA operon.…”

“…It also provides an integration point between both CcpA and CggR regulatory networks. A second link exists between these two networks (Tobisch et al, 1999;Fillinger et al, 2000;Ludwig et al, 2001) and has been elucidated recently by Stülke and coworkers: ccpA is necessary for the uptake of the PTS sugars and thus for the formation of FBP in the presence of this class of glycolytically metabolizable carbohydrates (Ludwig et al, 2002). Indeed, the kinase activity of HprK is increased in a ccpA mutant strain to such an extent that nearly all HPr molecules are phosphorylated on Ser-46; no more HPr is thus available for Pi transfer from PEP to the sugars to be taken up via the PTS Enzyme II permeases.…”

A phospho‐sugar binding domain homologous to NagB enzymes regulates the activity of the central glycolytic genes repressor

“…In Bacillus subtilis, as in many low G 1 C gram-positive bacteria, these enzymes are encoded by the hexacistronic gapA operon whose transcription is induced in response to the presence of a glycolytic carbon source in the culture medium. [2][3][4] ABSTRACT CggR belongs to the SorC family of bacterial transcriptional regulators which control the expression of genes and operons involved in carbohydrate catabolism. CggR was first identified in Bacillus subtilis where it represses the gapA operon encoding the five enzymes that catalyze the central part of glycolysis.…”

Regulated expression of HPrK/P does not affect carbon catabolite repression of thexynoperon and ofrocGinBacillus subtilis

“…This enzyme is constitutively expressed (Hanson et al, 2002) and its activity to phosphorylate HPr and Crh at conserved Ser46 residues using ATP or pyrophosphate as phosphate donors (Poncet et al, 2004) is controlled mainly by fructose-1,6-bisphosphate (FBP) (Deutscher & Saier, 1983;Kravanja et al, 1999;Jault et al, 2000). The resulting phospho-proteins serve as effectors enabling the pleiotropic regulator CcpA (catabolite control protein A) to bind its cognate DNA and regulate gene expression of numerous catabolic operons (Deutscher et al, 1995;Henkin, 1996;Tobisch et al, 1999). A drop in the intracellular FBP concentration triggers the phosphorylase activity of the enzyme, eventually resulting in derepression of CcpA controlled genes (Kravanja et al, 1999).…”