Amit R. Reddi, Ph.D.
Georgia Institute of Technology
An NIEHS grantee and colleagues have developed new fluorescent sensors and used them to track intracellular activity of the iron-containing compound known as heme. The research provides new insights into how cells make heme available in very low concentrations.
Although it can be toxic in larger amounts, miniscule amounts of heme work as an essential cofactor and signaling molecule. Many scientists viewed heme as a static compound that stays bound to the proteins with which it works.
The researchers used their new sensors to follow heme movement in yeast cells and observed, for the first time, that cells contain a variable pool of heme. The researchers also identified some of the biomolecules that help keep most of the pooled heme bound to proteins, while leaving a limited amount free for biochemical reactions. For example, they found that the signaling molecule nitric oxide can rapidly mobilize heme when it is needed for cellular processes such as regulating gene expression.
The new heme sensors can be used in multiple organisms to reveal fundamental aspects of heme dynamics.
Citation: Hanna DA, Harvey RM, Martinez-Guzman O, Yuan X, Chandrasekharan B, Raju G, Outten FW, Hamza I, Reddi AR. 2016. Heme dynamics and trafficking factors revealed by genetically encoded fluorescent heme sensors. PNAS; doi:10.1073/pnas.1523802113 [Online 31 May 2016].