The MAPK/ERK pathway is a crucial signaling cascade in cells that helps regulate various functions, including growth, differentiation, and survival. It is activated by external signals, such as growth factors, which bind to receptors on the cell surface. This activation triggers a series of proteins to communicate with each other, ultimately leading to the activation of the ERK protein. Once activated, ERK moves into the cell nucleus, where it influences gene expression and cellular responses. Dysregulation of the MAPK/ERK pathway can contribute to various diseases, including cancer, making it an important target for therapeutic interventions.