Cell Permeable Ratiometric Fluorescent Sensors for Imaging Phosphoinositides

Area of Science:

• Cell Biology
• Biochemistry
• Molecular Biology

Background:

• Phosphoinositides are vital cell-signal mediators on the plasma membrane.
• Their dynamic changes regulate cell signaling, and defects are linked to diseases like cancer and diabetes.
• Visualizing phosphoinositide distribution is key to understanding cell signaling.

Purpose of the Study:

• To develop selective, cell-permeable probes for quantifying phosphoinositides.
• To create peptide-based ratiometric fluorescent sensors for phosphoinositide imaging.
• To investigate phosphoinositide dynamics in live cells.

Main Methods:

• Development of short peptide-based ratiometric fluorescent sensors.
• Testing sensor selectivity for phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) and phosphatidylinositol-4-phosphate (PI4P).
• Assessing cell permeability and imaging using multiphoton excitation confocal microscopy.

Main Results:

• Sensors show selective response to PI(4,5)P2 and PI4P over other phospholipids.
• Probe affinity is up to 4 times higher for PI(4,5)P2 than PI4P.
• Sensors are cell-permeable, entering cells within 15 minutes and imaging phosphoinositides on cellular and organelle membranes.

Conclusions:

• Developed peptide-based sensors enable selective imaging of key phosphoinositides.
• These sensors facilitate quantification and monitoring of phosphoinositide signaling in live cells.
• The technology offers insights into cell signaling and related diseases.