Unconventional Cyclic di-GMP Signaling in Escherichia coli

• The species Escherichia coli represents an unfathomable variety of commensal, pathogenic, and environmental strains. The conventional cyclic di-GMP signaling in E. coli controls sessility-motility changes linked to commensalism and/or pathogenicity. Extraintestinal Pathogenic E. coli (ExPEC) are “commensals” that can cause an array of infections outside the gastrointestinal tract. To accommodate their pathogenic lifestyle with the commensal one, ExPEC biology is shaped not only by the presence of specific virulence genes and pathoadaptive mutations but also by regulatory adaptations. Bioinformatic and genetic studies indicate that the cyclic di-GMP signaling network is included in the adaptation process. For example, some neuroinvasive ExPEC were found to maintain reduced cyclic di-GMP levels due to RpoS deactivation, resulting in loss of appearance of the rugose morphotype. Moreover, ExPEC has a diversified repertoire of cyclic di-GMP degrading enzymes obtained by acquisition of novel genes often associated with fimbrial biogenesis gene clusters (e.g., sfaY/papY/focY) and by modification or deletion of specific core genome genes. For example, the majority of ExPEC contains a shortened allelic variant of the ycgG gene and some ExPEC strains do not even carry the genetic locus. New combinations of regulators offer a new cyclic di-GMP platform for S-fimbrial biogenesis and for new metabolic capabilities leading to citrate utilization and ferric citrate uptake. In this review, we outline the prerequisites for the unconventional signaling network, the rationale behind its existence in ExPEC, and future perspectives in studies of ExPEC.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Microbiology in the medical area (hsv//eng)

Nyckelord

ExPEC

NMEC

Pathoadaptation

RpoS

Citrate

Ferric citrate

S-fimbriae

mikrobiologi

Microbiology

Publikations- och innehållstyp

vet (ämneskategori)

kap (ämneskategori)