Cytoplasmic Escherichia coli ADPsugar pyrophosphatase binds to cell membranes in response to extracellular signals as the cell population density increases

MARÍA T. MORÁN ZORZANO; MANUEL MONTERO; FRANCISCO JOSÉ MUÑOZ; NORA ALONSO CASAJÚS; ALEJANDRO M. VIALE; GUSTAVO EYDALLÍN; MARÍA T. SESMA; EDURNE BAROJA FERNANDEZ; JAVIER POZUETA ROMERO

FEMS MICROBIOLOGY LETTERS

Blackwell

Año: 2008

0378-1097

ADP sugar pyrophosphatase (AspP) is a member of the ‘Nudix’ (Nucleoside diphosphate linked to some other moiety X) hydrolase family of enzymes that catalyzes the hydrolytic breakdown of ADP-glucose (ADPG) linked to glycogen biosynthesis. In a previous work, we showed that AspP activity is strongly enhanced by both glucose-1,6-bisphosphate and nucleotide–sugars, and by macromolecular crowding. In this work, we show that AspP binds to cell membranes as the bacterial population density increases, c. 30% of the total enzyme remaining membrane associated as glycogen depletes during the stationary phase. This process is not dependent on the stationary transcription factor RpoS, the producer of the bacterial quorum-sensing autoinducer 2 (LuxS), the presence of glycogen granules or glucose availability, but is stimulated by small soluble heat-labile molecule(s) occurring in cell-free spent supernatants of stationary cultures that are acid stabile and base labile. These data further point to AspP as a highly regulated enzyme, and provide a first set of evidences indicating that glycogen metabolism is subjected to regulation by intercellular communication in Escherichia coli.c. 30% of the total enzyme remaining membrane associated as glycogen depletes during the stationary phase. This process is not dependent on the stationary transcription factor RpoS, the producer of the bacterial quorum-sensing autoinducer 2 (LuxS), the presence of glycogen granules or glucose availability, but is stimulated by small soluble heat-labile molecule(s) occurring in cell-free spent supernatants of stationary cultures that are acid stabile and base labile. These data further point to AspP as a highly regulated enzyme, and provide a first set of evidences indicating that glycogen metabolism is subjected to regulation by intercellular communication in Escherichia coli.Escherichia coli.