Cell-Penetrating Peptides Enter Cells by Triggering Calcium Influx Through Orai1 Channels
Arginine-rich cell-penetrating peptides trigger direct cytosolic uptake by modulating the Orai1 calcium channel through cell surface sialic acids, establishing the molecular mechanism for rapid peptide import.
Quick Facts
What This Study Found
Rapid cytosolic CPP import depends on calcium influx via Orai1. Cell surface sialic acids mediate peptide-Orai1 interaction. Blocking Orai1 or sialic acids inhibited uptake; thapsigargin (Orai1 activator) reconstituted uptake at low peptide concentrations.
Key Numbers
CPPs >10 μM activated Orai1; calcium influx triggered ASMase; resulted in rapid cytosolic import.
How They Did This
In vitro studies with arginine-rich CPPs at various concentrations. Calcium channel modulators (thapsigargin, Orai1 blockers). Sialylation inhibition and chemical sialic acid blocking. Fluorescent peptide uptake quantification.
Why This Research Matters
Understanding exactly how CPPs enter cells is crucial for optimizing peptide drug delivery. This Orai1-calcium mechanism provides specific molecular targets for enhancing or controlling peptide uptake into cells.
The Bigger Picture
Cell-penetrating peptides are widely used in drug delivery research but their mechanism of entry has been debated. This discovery of the Orai1-calcium-ASMase pathway provides the first complete molecular chain from initial cell contact to cytosolic delivery.
What This Study Doesn't Tell Us
In vitro cell culture system — in vivo CPP uptake may involve additional mechanisms. The 10 μM threshold may not be achievable for all therapeutic applications. Cell type-specific Orai1 expression could affect generalizability.
Questions This Raises
- ?Can Orai1 modulation be used to enhance CPP-mediated drug delivery at lower peptide concentrations?
- ?Does this mechanism apply to all types of cell-penetrating peptides or only arginine-rich ones?
- ?Could tissue-specific Orai1 expression be exploited for targeted peptide delivery?
Trust & Context
- Key Stat:
- Orai1 calcium channel identified as the molecular trigger for cell-penetrating peptide cytosolic uptake
- Evidence Grade:
- Rigorous in vitro mechanistic study with multiple complementary approaches (pharmacological inhibition, genetic modulation, reconstitution experiments).
- Study Age:
- Published in 2020. CPP uptake mechanisms continue to be refined with this Orai1 pathway as a key framework.
- Original Title:
- Modulation of Orai1 by cationic peptides triggers their direct cytosolic uptake.
- Published In:
- Biochimica et biophysica acta. Biomembranes, 1862(3), 183155 (2020)
- Authors:
- Zuconelli, Cristiane R, Schmidt, Samuel(2), Wallbrecher, Rike, van Oostrum, Jenny, Bartels, Yvonne L, Didan, Yuliia, Berendsen, Mike L T, Brock, Roland, Adjobo-Hermans, Merel J W
- Database ID:
- RPEP-05246
Evidence Hierarchy
Frequently Asked Questions
What is Orai1?
Orai1 is a calcium channel in cell membranes that controls calcium flow into cells. This study shows it's the molecular 'gatekeeper' that cell-penetrating peptides trigger to gain entry into cells.
Why does it matter how peptides enter cells?
Many peptide drugs need to reach targets inside cells to work. Understanding the exact entry mechanism allows scientists to design better drug delivery systems that can get therapeutic peptides where they need to go.
Read More on RethinkPeptides
Cite This Study
https://rethinkpeptides.com/research/RPEP-05246APA
Zuconelli, Cristiane R; Schmidt, Samuel; Wallbrecher, Rike; van Oostrum, Jenny; Bartels, Yvonne L; Didan, Yuliia; Berendsen, Mike L T; Brock, Roland; Adjobo-Hermans, Merel J W. (2020). Modulation of Orai1 by cationic peptides triggers their direct cytosolic uptake.. Biochimica et biophysica acta. Biomembranes, 1862(3), 183155. https://doi.org/10.1016/j.bbamem.2019.183155
MLA
Zuconelli, Cristiane R, et al. "Modulation of Orai1 by cationic peptides triggers their direct cytosolic uptake.." Biochimica et biophysica acta. Biomembranes, 2020. https://doi.org/10.1016/j.bbamem.2019.183155
RethinkPeptides
RethinkPeptides Research Database. "Modulation of Orai1 by cationic peptides triggers their dire..." RPEP-05246. Retrieved from https://rethinkpeptides.com/research/zuconelli-2020-modulation-of-orai1-by
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkPeptides research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.