A Genetically Encoded FRET Sensor for Hypoxia and Prolyl Hydroxylases

Area of Science:

• Biochemistry
• Molecular Biology
• Cell Biology

Background:

• Oxygen is essential for aerobic life, and its regulation involves hypoxia-inducible factor (HIF)-1α.
• Prolyl hydroxylase domain enzymes (PHDs) control HIF-1α hydroxylation, a key step in oxygen sensing and gene expression.
• Understanding PHD activity is crucial for studying cellular responses to hypoxia.

Purpose of the Study:

• To develop a genetically encoded fluorescent sensor for monitoring PHD activity.
• To investigate cellular oxygen sensing mechanisms using the developed sensor.
• To determine the subcellular localization of HIF-prolyl hydroxylase activity.

Main Methods:

• Development of a dual-emission ratiometric fluorescent sensor (ProCY).
• In vitro and live-cell assays to detect PHD activity.
• Targeting ProCY to different cellular compartments (nucleus and cytosol).
• Monitoring hypoxia in mammalian cells using ProCY.

Main Results:

• ProCY successfully responded to PHD activities in vitro and in live cells.
• The sensor demonstrated the ability to monitor hypoxia in mammalian cells.
• HIF-prolyl hydroxylase activity was primarily localized in the cytosol of HEK 293T cells under normoxic conditions.

Conclusions:

• ProCY is a versatile tool for evaluating hypoxia and PHD activity.
• The sensor facilitates a deeper understanding of hypoxic response pathways.
• This work provides insights into the spatial regulation of oxygen sensing in cells.