GPN does not release lysosomal Ca<sup>2+</sup> but evokes Ca<sup>2+</sup> release from the ER by increasing the cytosolic pH independently of cathepsin C.
Van Marrewijk, Laura
Journal of cell science
The Company of Biologists Ltd.
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Atakpa, P., Van Marrewijk, L., Apta-Smith, M., Chakraborty, S., & Taylor, C. (2019). GPN does not release lysosomal Ca<sup>2+</sup> but evokes Ca<sup>2+</sup> release from the ER by increasing the cytosolic pH independently of cathepsin C.. Journal of cell science, 132 (3)https://doi.org/10.1242/jcs.223883
GPN (glycyl-L-phenylalanine 2-naphthylamide) is widely used to perturb lysosomes because its cleavage by the lysosomal enzyme, cathepsin C, is proposed to rupture lysosomal membranes. We show that GPN evokes a sustained increase in lysosomal pH (pHly), and transient increases in cytosolic pH (pHcyt) and Ca2+ concentration ([Ca2+]c). None of these effects require cathepsin C, nor are they accompanied by rupture of lysosomes, but they are mimicked by structurally unrelated weak bases. GPN-evoked increases in [Ca2+]c require Ca2+ within the ER, but they are not mediated by ER Ca2+ channels amplifying Ca2+ release from lysosomes. GPN increases [Ca2+]c by increasing pHcyt, which then directly stimulates Ca2+ release from the ER. We conclude that physiologically relevant increases in pHcyt stimulate Ca2+ release from the ER independent of IP3 and ryanodine receptors, and that GPN does not selectively target lysosomes.
Leukocytes, Cell Line, Tumor, Hela Cells, Lysosomes, Endoplasmic Reticulum, Cytosol, Humans, Calcium, Dipeptides, Calcium Channels, Ryanodine Receptor Calcium Release Channel, Calcium Signaling, Gene Expression, Biological Transport, Ploidies, Hydrogen-Ion Concentration, Lysosome-Associated Membrane Glycoproteins, Inositol 1,4,5-Trisphosphate Receptors, Gene Knockdown Techniques, Cathepsin C, HEK293 Cells, CRISPR-Cas Systems, Gene Editing
Wellcome Trust (101844/Z/13/Z)
External DOI: https://doi.org/10.1242/jcs.223883
This record's URL: https://www.repository.cam.ac.uk/handle/1810/288565
Attribution 4.0 International
Licence URL: https://creativecommons.org/licenses/by/4.0/