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.
View / Open Files
Publication Date
2019-02Journal Title
Journal of cell science
ISSN
0021-9533
Publisher
The Company of Biologists Ltd.
Volume
132
Issue
3
Language
eng
Type
Article
This Version
VoR
Physical Medium
Electronic
Metadata
Show full item recordCitation
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
Abstract
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.
Keywords
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
Sponsorship
Wellcome Trust (101844/Z/13/Z)
BBSRC (BB/P005330/1)
Identifiers
External DOI: https://doi.org/10.1242/jcs.223883
This record's URL: https://www.repository.cam.ac.uk/handle/1810/288565