Measuring intranuclear and nuclear envelope [Ca(2+)] vs. cytosolic [Ca (2+)].

Area of Science:

• Cellular Biology
• Biochemistry
• Physiology

Background:

• Nuclear calcium ions (Ca2+) regulate essential cellular functions like gene expression and apoptosis.
• Accurate quantification of subcellular Ca2+ signals is crucial for understanding cellular processes.
• Fluorescent indicator properties can vary in different cellular compartments, complicating Ca2+ concentration measurements.

Purpose of the Study:

• To develop and validate technical approaches for reliable subcellular quantification of Ca2+.
• To differentiate and measure Ca2+ concentrations in the cytoplasm, nucleus, and nuclear envelope.
• To address the challenges of translating fluorescence changes into accurate Ca2+ concentrations.

Main Methods:

• Utilized fluorescein-derived fluorescent indicators, specifically Fluo-4 and Fluo-5N.
• Employed in situ calibration techniques for accurate measurements.
• Focused on distinguishing Ca2+ signals between the cytoplasm and nucleus.

Main Results:

• Established reliable methods for subcellular Ca2+ quantification.
• Successfully differentiated and measured [Ca2+] in the cytoplasm, nucleus, and nuclear envelope.
• Demonstrated the effectiveness of in situ calibration for accurate quantitative analysis.

Conclusions:

• The developed technical approaches enable reliable subcellular Ca2+ quantification.
• Accurate measurement of nuclear and cytoplasmic Ca2+ is achievable using calibrated fluorescent indicators.
• This work provides essential tools for studying Ca2+-dependent cellular processes.