👉 In the context of molecular biology, an "estrin" is a protein that plays a role in the regulation of cell signaling pathways. Specifically, it was first identified as a component of the ERK signaling pathway by scientists at the University of California, Berkeley, and later discovered to be involved in other signaling pathways including the PI3K/AKT and mTOR signaling pathways. An "estrin" is a type of protein that binds to its receptor and can then activate or inhibit the activity of