How Phosphotransferase System-Related Protein Phosphorylation Regulates Carbohydrate Metabolism in Bacteria

Abstract

SUMMARY The phosphoenolpyruvate(PEP):carbohydrate phosphotransferase system (PTS) is found only in bacteria, where it catalyzes the transport and phosphorylation of numerous monosaccharides, disaccharides, amino sugars, polyols, and other sugar derivatives. To carry out its catalytic function in sugar transport and phosphorylation, the PTS uses PEP as an energy source and phosphoryl donor. The phosphoryl group of PEP is usually transferred via four distinct proteins (domains) to the transported sugar bound to the respective membrane component(s) (EIIC and EIID) of the PTS. The organization of the PTS as a four-step phosphoryl transfer system, in which all P derivatives exhibit similar energy (phosphorylation occurs at histidyl or cysteyl residues), is surprising, as a single protein (or domain) coupling energy transfer and sugar phosphorylation would be sufficient for PTS function. A possible explanation for the complexity of the PTS was provided by the discovery that the PTS also carries out numerous regulatory functions. Depending on their phosphorylation state, the four proteins (domains) forming the PTS phosphorylation cascade (EI, HPr, EIIA, and EIIB) can phosphorylate or interact with numerous non-PTS proteins and thereby regulate their activity. In addition, in certain bacteria, one of the PTS components (HPr) is phosphorylated by ATP at a seryl residue, which increases the complexity of PTS-mediated regulation. In this review, we try to summarize the known protein phosphorylation-related regulatory functions of the PTS. As we shall see, the PTS regulation network not only controls carbohydrate uptake and metabolism but also interferes with the utilization of nitrogen and phosphorus and the virulence of certain pathogens.

A dual function for a bacterial small RNA: SgrS performs base pairing-dependent regulation and encodes a functional polypeptide

“…The glucosespecific PTS enzyme IIA Glc phosphorylates IICB Glc (PtsG) and also has important regulatory functions in carbon catabolite repression (18). The regulatory functions of IIA Glc depend on its phosphorylation state, which in turn depends on IICB Glc transport activity.…”

Expression, purification, crystallization and preliminary X-ray analysis of the EIICGlcdomain of theEscherichia coliglucose transporter

“…EIIA Glc , a monomeric all-protein, transfers phosphoryl groups from HPr to the EIIB Glc domain. It is also an allosteric regulator of adenylate cyclase, glycerol kinase, the lactose/proton symporter and other non-PTS transporters and as such plays a key role in E. coli catabolite repression (Deutscher et al, 2006). Homodimeric EIICB Glc consists of two domains (Buhr et al, 1994; Fig.…”

“…In addition to carbohydrate uptake, the PTS also controls carbon and nitrogen metabolism, chemotaxis, biofilm formation and other bacterial behaviours (Lux et al, 1995(Lux et al, , 1999Erni, 2006;Deutscher et al, 2006;Houot & Watnick, 2008;Poncet et al, 2009). The PTS is at the heart of a regulatory network known as carbon catabolite repression (Gorke & Stulke, 2008).…”

“…Most cells take up glucose by facilitated diffusion or cation symporters. Many bacteria, including Escherichia coli, accumulate glucose and other carbohydrates by group translocation, a mechanism that couples translocation with concomitant phosphorylation of the transported solute (Siebold et al, 2001;Deutscher et al, 2006). Phosphoenolypyruvate (PEP), an intermediate of glycolysis, is the phosphoryl donor (Kundig et al, 1964).…”

Solution Structure of the IIAChitobiose-IIBChitobiose Complex of the N,N′-Diacetylchitobiose Branch of the Escherichia coli Phosphotransferase System

“…The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) 3 couples a phosphorylation cascade involving a sequential series of bimolecular protein-protein complexes to active sugar translocation across the membrane and to regulation of an array of cellular processes, including carbon catabolite repression (1)(2)(3)(4)(5)(6). The first two steps of the PTS, involving autophosphorylation of enzyme I (EI) by phosphoenolpyruvate and subsequent phosphoryl transfer to the histidine phosphocarrier protein (HPr), are common to all branches of the pathway.…”