"The discovery comes from detailed studies of the transmembrane protein straddling the worlds inside and outside of lymphocytes and other cells of the immune system. These receptor proteins are like spokes piercing the cell membrane. Part of the receptor pokes into the cell and part extends out from the cell surface. The external "domain" receives signals from outside the cell which regulate responses inside -- ranging from increasing the cell's glucose supply to starting a new cell division cycle to generate more lymphocytes."
"Typical nuclear receptor proteins are like sensors, registering a specific molecular event and responding accordingly, generally by altering gene expression patterns. So, Lazar asked, "What is the purpose of having a system that responds to changes in cellular heme levels?" He hypothesized that the sensor could act to regulate heme itself."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.