Selective visualization of GLUT4 storage vesicles and associated Rab proteins using IRAP-pHluorin

Area of Science:

• Cell Biology
• Molecular Biology
• Biophysics

Background:

• Fluorescence microscopy and fluorescent protein (FP)-tagged GLUT4 are crucial for studying GLUT4 localization and dynamics.
• Distinguishing GLUT4 storage vesicles (GSVs) from other intracellular compartments in live cells remains challenging.

Purpose of the Study:

• To develop a method for selectively visualizing GSVs in live cells.
• To identify proteins associated with GSVs.

Main Methods:

• Utilized IRAP-pHluorin, a pH-sensitive fluorescent reporter.
• Employed total internal reflection fluorescence (TIRF) microscopy for enhanced visualization of cell-surface and near-surface events.
• Combined these techniques to track GSVs and associated Rab proteins.

Main Results:

• Successfully visualized and distinguished GSVs from other GLUT4-containing compartments.
• Identified specific Rab proteins associated with GSVs.
• Demonstrated the utility of the assay for defining GSV identity through protein association.

Conclusions:

• IRAP-pHluorin and TIRF microscopy provide a powerful tool for selective GSV visualization.
• This method enhances the study of GLUT4 trafficking and GSV composition.
• The assay aids in unraveling the molecular machinery governing GLUT4 storage and release.