autocrine signaling

Autocrine signaling is a cell talking to itself — or, more precisely, sending a note out the door and then reading it back when it returns. The cell secretes a messenger and also carries the receptor for that very messenger, so it responds to its own output.

Formally, autocrine signaling is a mode of communication in which a cell secretes a molecule that binds receptors on the same cell that released it. This can create self-reinforcing loops: a cell that responds to its own signal can amplify or sustain its own activity. It is widespread in growth-factor biology and in the immune system, where activated T cells make and respond to their own interleukin-2.

In endocrinology, autocrine actions help fine-tune how strongly a cell responds and can lock cells into proliferative states. A caveat: autocrine signaling becomes clinically important in cancer, where tumor cells may secrete a growth factor and the receptor for it, driving their own uncontrolled growth without waiting for outside instructions.