Regulated dynamic subcellular GLUT4 localization revealed by proximal proteome mapping in human muscle cells

Area of Science:

• Cellular Biology
• Metabolism
• Molecular Biology

Background:

• Glucose transport is crucial for whole-body metabolism.
• GLUT4 (SLC2A4) in the plasma membrane of muscle and fat cells regulates glucose uptake.
• Physiological signals like insulin receptor and AMPK activate GLUT4.

Purpose of the Study:

• To investigate the dynamic regulation of GLUT4 distribution in human muscle cells.
• To elucidate the role of AMPK in controlling GLUT4 trafficking.
• To map the protein interactions and cellular compartments involved in GLUT4 transport.

Main Methods:

• APEX2 proximity mapping to identify interacting proteins.
• Analysis of GLUT4 localization in unstimulated and stimulated muscle cells.
• Investigation of exocytosis and endocytosis pathways regulated by AMPK.

Main Results:

• AMPK dynamically regulates GLUT4 distribution between the plasma membrane and intracellular compartments.
• AMPK-mediated exocytosis involves Rab10 and TBC1D4.
• GLUT4 is trafficked through both PM-proximal and PM-distal compartments, including the Golgi and trans-Golgi network.
• AMPK stimulation recruits GLUT4 from Golgi compartments to the plasma membrane.

Conclusions:

• AMPK plays a key role in controlling GLUT4 translocation to the plasma membrane.
• The study provides a high-resolution map of GLUT4 localization and trafficking pathways.
• This framework aids in understanding molecular mechanisms of GLUT4 regulation by various signaling inputs.