ABSTRACT
Transient changes in intracellular pH (pHi) have been shown to regulate normal cell behaviors like migration and cell-cycle progression, while dysregulated pHi dynamics are a hallmark of cancer. However, little is known about how pHi heterogeneity and dynamics influence population-level measurements or single-cell behaviors. Here, we present and characterize single-cell pHi heterogeneity distributions in both normal and cancer cells and measure dynamic pHi increases in single cells in response to growth factor signaling. Next, we measure pHi dynamics in single cells during cell cycle progression. We determined that single-cell pHi is significantly decreased at the G1/S boundary, increases from S phase to the G2/M transition, rapidly acidifies during mitosis, and recovers in daughter cells. This sinusoidal pattern of pHi dynamics was linked to cell cycle timing regardless of synchronization method. This work confirms prior work at the population level and reveals distinct advantages of single-cell pHi measurements in capturing pHi heterogeneity across a population and dynamics within single cells.
SUMMARY Spear et al., characterizes an approach for measuring single-cell intracellular pH (pHi) and monitors both single-cell pHi responses to key extracellular signaling cues and pHi dynamics during cell cycle progression. By tracking pHi in single cells, Spear et al. confirms prior work at the population level showing an increase in pHi at the G2/M transition. However, these single-cell pHi measurements reveal new features of pHi dynamics during cell cycle progression, including significantly decreased pHi at the G1/S boundary and rapid acidification during mitosis.
Competing Interest Statement
The authors have declared no competing interest.
