Yeast cells use glucose to obtain energy and as a signaling substance. As the cells take up glucose, the pH value of the cell increases within minutes. Researchers in the group of Matthias Peter, ETH Zurich, Switzerland, have discovered that the high pH value is detected by the sensor protein, V-ATPase which triggers cell growth. Low pH values were artificially maintained in the presence of glucose which lead to no cell growth despite the abundance of food source.

The pH value could be a universal growth signal for cells as pancreatic cells were also shown to grow when the pH value is raised. Additionally, the pH value of tumor cells, which divide much more quickly than healthy cells, is higher than for dormant cells.

Further elucidation of this mechanism could mean that rather than having to identify each nutrient, pH could be monitored instead.

• Cytosolic pH is a second messenger for glucose and regulates the PKA pathway through V-ATPase
  R. Dechant, M. Binda, S. S. Lee, S. Pelet, J. Winderickx, M. Peter,
  EMBO J. 2010, 29, 2515 – 2526.
  DOI: 10.1038/emboj.2010.138