Metal Ion Sensors

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Metal Ion Sensors with Improved Properties Inventor Jenny Yang Patent Status Patent pending GSU Case Number 2006-21 Introduction There is a widespread interest in developing robust metal ion sensors to probe the significance of metals in cellular signaling. One such example is the need for Ca2+ sensors with minimum interference towards natural Ca2+ binding proteins and exhibiting binding affinities at various cellular compartments such as endoplasmic reticulum (ER). Presently available Ca2+ sensors need improvement at many levels. Technology Georgia State University researchers have devised a novel strategy for designing efficient metal sensors using Ca2+ sensors as a model system. They have obtained a fluorescent sensor to detect metal ions comprising a fluorescent protein and an engineered metal binding site. Specifically, a Ca2+ binding motif was engineered into sensitive locations of a single fluorescent protein without using FRET pairs. These sensors are stable up to 37 ºC and have been extensively examined for their optical and metal binding properties, including kinetics for dynamic Ca2+ monitoring. They have been successfully targeted at ER to monitor agonist induced changes in mammalian cells. Applications Tools to study the contribution of cellular compartments in metal ion signaling Advantages Improved thermal and optical properties. Operates up to 37 ºC Large ratiometric fluorescence and absorbance changes upon Ca2+ binding Binding affinities correspond to ER Ca2+ concentration (Kd values = 0.4 - 2 mM) Accurate monitoring of Ca2+ dynamics in living cells