LipR functions as an intracellular pH regulator in under glucose conditions.

Intracellular pH critically affects various biological processes, and an appropriate cytoplasmic pH is essential for ensuring bacterial growth. Glucose is the preferred carbon source for most heterotrophs; however, excess glucose often causes the accumulation of acidic metabolites, lowering the intracellular pH and inhibiting bacterial growth. can effectively cope with glucose-induced stress; unfortunately, little is known about the regulators involved in this process. Here, we document that the target of the dual-function sRNA YhfH, the gene, encodes a LacI-family transcription factor LipR as an intracellular pH regulator when BMB171 is suddenly exposed to glucose. Under glucose conditions, deletion leads to early growth arrest by causing a rapid decrease in intracellular pH (~5.4). Then, the direct targets and a binding motif (GAWAWCRWTWTCAT) of LipR were identified based on the electrophoretic mobility shift assay, the DNase-I footprinting assay, and RNA sequencing, and the gene encoding a key enzyme in glycolysis was directly inhibited by LipR. Furthermore, Ni is considered a possible effector for LipR. In addition to YhfH, the expression was coregulated by itself, CcpA, and AbrB. Our study reveals that LipR plays a balancing role between glucose metabolism and intracellular pH in subjected to glucose stress.