Sugar accumulation in Gram-positive bacteria: exclusion and expulsion mechanisms

Abstract

Bacteria use a diverse range of mechanisms to regulate sugar accumulation in response to internal and external energy availability. Uptake of sugars is regulated by exclusion mechanisms while the intracellular sugar phosphate concentration is modulated in certain Gram-positive bacteria by an expulsion mechanism. Recent evidence suggests that a regulatory protein of the phosphotransferase system catalyses ATP-dependent phosphorylation of the phosphocarrier protein, HPr, thereby controlling sugar accumulation by exclusion and/or expulsion processes.