Imaging Measurement of Lysosomal Calcium

Lysosomes are the second largest intracellular Ca²⁺ store and are now key players in the generation and response to intracellular Ca²⁺ signaling. At the same time, Ca²⁺ release from lysosomes is critical in a variety of biological processes that maintain cellular homeostasis. CD BioSciences' expertise in lysosomes provides strong support for lysosomal calcium imaging measurements. Our advanced technology platform will bring you efficient and economical service, ensuring your 100% satisfaction.

Lysosomal Calcium

In mammals, lysosomes typically comprise 2-3% of the cell volume, and although lysosomes have higher luminal Ca²⁺ concentrations, their overall contribution to global cellular Ca²⁺ signaling is lower relative to the endoplasmic reticulum. Lysosomes have been shown to initiate global changes in cellular Ca²⁺ signaling. Lysosomes actively sequester Ca²⁺ within their lumen and release it into the cytoplasm upon activation of endolysosomal Ca²⁺ channels. Lysosomal Ca²⁺ signaling is required for a variety of cellular processes, including signal transduction, vesicular transport, autophagy, nutrient sensing, cytosolic action, and membrane repair. In addition, dysregulation of endolysosomal Ca²⁺ homeostasis underlies a variety of mammalian diseases. With the development of organelle-specific physiological and imaging methods, real-time imaging of lysosomal Ca²⁺ indicators has become possible. This is of great significance for in-depth study of the importance of Ca²⁺ to endolysosomal biology and how endolysosomes regulate Ca²⁺.

Fig. 1. Approaches for assessing endolysosomal Ca²⁺ content. (Morgan AJ, et al., 2015)

Services

Accurate measurement of lysosomal Ca²⁺ is complicated by acidic pH and signal crossover between lysosomal and other intracellular Ca²⁺ stores. For many years, CD BioSciences has been working to measure lysosomal Ca²⁺ by a variety of methods. Our advanced whole lysosome membrane clamp technology, single organelle planar membrane clamp and genetic coding provide powerful support for real-time imaging of lysosomal Ca²⁺ indicators. Our bioscientists focus on the following lysosomal Ca²⁺ measurements.

1. Overall cytosolic Ca²⁺ measurements.
2. Intraluminal Ca²⁺ measurements.

We offer a variety of strategies to achieve accurate lysosomal Ca²⁺ measurements as described below. Depending on your project requirements, we will develop the best solution for your lysosomal Ca²⁺ measurement.

Indirect Monitoring with Cytosolic Ca²⁺ Indicators

We monitor the appearance of Ca²⁺ in the cytosol by selectively draining the endolysosomal Ca²⁺ stores and using conventional Ca²⁺ dyes.

• An indirect and simple method for measuring endolysosomal Ca²⁺ content.
• Requires standard fluorometric equipment and readily available reagents.
• This method of assaying endolysosomal Ca²⁺ content can provide a useful indication or preliminary screening, but it is not conclusive, only qualitative.

Direct Monitoring with Intraluminal Fluorescent Probe

We use dextrose ring-conjugated fluorescent dyes to simultaneously measure intraluminal lysosomal calcium and pH. In addition, we use the lysosomal membrane proteins LAMP-1 and TRPML1 to create lysosome-specific Ca²⁺ reporter factors.

• Ca²⁺ reporter factors are measured by genetic encoding.
• These probes can detect cytoplasmic changes in Ca²⁺ in the region surrounding the lysosome.
• Real-time dynamic monitoring of lysosomal Ca²⁺.

Our professional services for imaging measurement of lysosomal calcium have been well received by customers. Our highly skilled and dedicated scientific staff ensures that the most appropriate method and technology is selected for each specialized lysosomal project. If you have any special requirements about our services, please feel free to contact us. We are looking forward to working together with your attractive projects.

Reference

1. Morgan AJ, Davis LC, Galione A. (2015) Imaging approaches to measuring lysosomal calcium. Methods Cell Biol. 126:159-95.