Measuring Ca²⁺ Levels in Subcellular Compartments with Genetically Encoded GFP-Based Indicators.

Area of Science:

• Cell Biology
• Biochemistry
• Pathology

Background:

• Cellular calcium (Ca2+) homeostasis is essential for eukaryotic cell function and survival.
• Disruptions in Ca2+ homeostasis are implicated in numerous pathological conditions.
• Monitoring Ca2+ fluxes in subcellular compartments is critical for understanding cellular dysfunction.

Purpose of the Study:

• To describe a protocol for measuring mitochondrial calcium levels using a genetically encoded indicator.
• To enable rapid assessment of mitochondrial Ca2+ homeostasis alterations in various experimental contexts.
• To provide a tool for investigating pathological pathways involving mitochondrial Ca2+ dysregulation.

Main Methods:

• Utilizing the GCaMP6f probe genetically encoded and targeted to mitochondria (4mtGCaMP).
• Measuring mitochondrial calcium levels in resting conditions in HeLa cells.
• Employing GFP-based indicators that change spectral properties upon Ca2+ binding.

Main Results:

• The described protocol allows for easy and quick registration of mitochondrial calcium levels.
• The method is applicable to different cell populations and experimental settings.
• The 4mtGCaMP probe effectively reports on mitochondrial Ca2+ status.

Conclusions:

• This protocol offers a valuable tool for studying mitochondrial Ca2+ homeostasis.
• It facilitates the unraveling of pathogenic pathways linked to calcium dysregulation.
• Accurate measurement of mitochondrial Ca2+ is key to understanding cellular health and disease.