Related Experiment Video
Updated: Apr 21, 2026

Isolation of Peritoneum-derived Mast Cells and Their Functional Characterization with Ca2+-imaging and Degranulation Assays
Published on: July 4, 2018
Distinct phosphoinositide signatures orchestrate FcεRI versus MRGPRX2 mast cell secretion
Sewar Omari-Manaa1, Roselyn Aharonov1, Stephen J Galli2
1Department of Cell, Developmental and Regenerative Biology, Gray Faculty of Medical and Health Sciences, Tel Aviv University, Tel Aviv 6997801, Israel.
Abstract:
Phosphoinositides (PIs) regulate mast cell (MC) secretory granule (SG) biogenesis and exocytosis, yet their compartment-specific roles in receptor signaling and secretion remain unclear. Using a rapamycin-inducible dimerization system to recruit site-specific lipid phosphatases to either the plasma membrane or the SGs, we assessed the impact of spatially restricted PI depletion on secretion triggered by FcεRI activation, the MRGPRX2 ligand substance P (SP), or receptor-independent calcium/phorbol ester stimulation. Our data reveal distinct and shared PI requirements for coupling FcεRI and MRGPRX2 signaling to the exocytic machinery and uncover PI derivatives that act locally at the SGs to modulate granule release. Together, these findings show that individual PIs differentially orchestrate allergic and neurogenic secretion pathways and fine-tune SG exocytosis through site-specific functions.
Related Concept Videos
IP3/DAG Signaling Pathway
Phosphoinositides and PIPs
Different phosphoinositides are synthesized and recruited on the cytosolic face of the plasma membrane. The localization of specific phosphoinositides concentrated in separate membrane...
Amplifying Signals via Second Messengers
Intracellular Signaling Affects Focal Adhesions
Some...
What are Second Messengers?
Assembly of Signaling Complexes
Interaction domains in cell signaling
Interaction domains recognize exposed features of their binding partners containing post-translationally modified sequences,...

