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Updated: Jul 19, 2026

Single-molecule Super-resolution Imaging of Phosphatidylinositol 4,5-bisphosphate in the Plasma Membrane with Novel Fluorescent Probes
Published on: October 15, 2016
Plasma membrane IP3 receptors
1Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD, UK. cwt1000@cam.ac.uk
Inositol 1,4,5-trisphosphate receptors (IP3Rs) function in the plasma membrane, mediating significant calcium (Ca2+) entry in DT40 cells. This Ca2+ influx via IP3Rs has distinct cellular effects compared to store-operated channels.
Area of Science:
- Cellular Biology
- Molecular Physiology
- Ion Channel Function
Background:
- Inositol 1,4,5-trisphosphate receptors (IP3Rs) are primarily known for their role in intracellular calcium signaling.
- Their presence and function within the plasma membrane of animal cells remain largely uncharacterized.
Purpose of the Study:
- To investigate the presence and functional role of IP3Rs in the plasma membrane.
- To determine the contribution of plasma membrane IP3Rs to calcium (Ca2+) entry in DT40 cells.
Main Methods:
- Whole-cell patch-clamp electrophysiology was employed on DT40 cells.
- Studies utilized cells expressing native or mutated forms of IP3Rs.
Main Results:
- DT40 cells express a small number (two to three) of functional IP3Rs in their plasma membrane.
- Approximately 50% of B-cell receptor-stimulated Ca2+ entry is mediated by these plasma membrane IP3Rs, not solely by store-operated Ca2+ entry.
- Ca2+ entry through the few large-conductance plasma membrane IP3Rs differs functionally from entry via numerous low-conductance store-operated channels.
Conclusions:
- Plasma membrane IP3Rs are significant contributors to cellular calcium homeostasis.
- The distinct conductance and number of these channels suggest unique roles in cellular signaling pathways.
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