Special Section on Protein Photonics for Imaging, Sensing, and Manipulation: Honoring Prof. Osamu Shimomura, a Pioneer of Photonics for Biomedical Research

MagIC, a genetically encoded fluorescent indicator for monitoring cellular Mg2+ using a non-Förster resonance energy transfer ratiometric imaging approach

[+] Author Affiliations
Vadim Pérez Koldenkova, Tomoki Matsuda, Takeharu Nagai

Osaka University, Institute of Scientific and Industrial Research, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan

J. Biomed. Opt. 20(10), 101203 (Aug 05, 2015). doi:10.1117/1.JBO.20.10.101203
History: Received January 1, 2015; Accepted April 21, 2015
Text Size: A A A

Abstract.  Intracellular Mg2+ roles are commensurate with its abundance in the cell cytoplasm. However, little is known about Mg2+ subcellular dynamics, primarily due to the lack of suitable Mg2+-selective tools to monitor this ion in intracellular compartments. To cope with this lack, we developed a Mg2+-sensitive indicator—MagIC (indicator for Magnesium Imaging in Cell) —composed of a functionalized yellow fluorescent protein (FP) variant fused to a red-emitting FP serving as a reference, thus allowing ratiometric imaging of Mg2+. MagIC expressed in mammalian cells is homogeneously distributed between the cytosol and nucleus but its fusion with appropriate targeting sequences redirects it to mitochondria or the endoplasmic reticulum. MagIC shows little interference by intracellular Ca2+ [Kd(Mg2+)=5.1mM; Kd(Ca2+)=4.8mM] and its kinetic properties (koff=84s1) approach those of indicator dyes. With MagIC, as reported previously, we also observed a cytosolic Mg2+ increase provoked by application of 50 mM MgCl2 in the medium. This effect is, however, mimicked by 75 mM KCl or 150 mM d-sorbitol addition, indicating that it is a response to the associated hyperosmotic shock and not to Mg2+ itself. Our results confirm the functionality of MagIC as a useful tool for the long-awaited possibility of prolonged and organelle-specific monitoring of cellular Mg2+.

Figures in this Article
© 2015 Society of Photo-Optical Instrumentation Engineers

Citation

Vadim Pérez Koldenkova ; Tomoki Matsuda and Takeharu Nagai
"MagIC, a genetically encoded fluorescent indicator for monitoring cellular Mg2+ using a non-Förster resonance energy transfer ratiometric imaging approach", J. Biomed. Opt. 20(10), 101203 (Aug 05, 2015). ; http://dx.doi.org/10.1117/1.JBO.20.10.101203


Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging & repositioning the boxes below.

Related Book Chapters

Topic Collections

PubMed Articles
Advertisement
  • Don't have an account?
  • Subscribe to the SPIE Digital Library
  • Create a FREE account to sign up for Digital Library content alerts and gain access to institutional subscriptions remotely.
Access This Article
Sign in or Create a personal account to Buy this article ($20 for members, $25 for non-members).
Access This Proceeding
Sign in or Create a personal account to Buy this article ($15 for members, $18 for non-members).
Access This Chapter

Access to SPIE eBooks is limited to subscribing institutions and is not available as part of a personal subscription. Print or electronic versions of individual SPIE books may be purchased via SPIE.org.