Autokrín

Autocrín, also known as autocrine signaling, is a form of cell communication in which a cell secretes signaling molecules that bind to receptors on its own surface or on neighboring cells of the same type. This self-targeting can stimulate or inhibit the secreting cell, helping coordinate behavior within a tissue or cell population. The signaling molecules involved are diverse and include cytokines, growth factors, and other small peptides or lipids.

Autocrine signaling is one of the basic modes of cell signaling. It differs from paracrine signaling, which affects nearby different cells; endocrine signaling, where factors travel through the bloodstream to distant targets; and juxtacrine signaling, which requires direct cell-to-cell contact. Autocrine loops are important in immune activation, development, and tissue repair, where cells rely on self-generated cues to regulate growth and differentiation. In cancer, autocrine growth factor signaling can contribute to uncontrolled proliferation and survival by sustaining self-stimulation.

Mechanistically, a cell must produce and secrete ligands and maintain expression of compatible receptors. Regulation of autocrine signaling can involve feedback loops, receptor up- or down-regulation, and cross-talk with other pathways. The term derives from auto- meaning self and crine from the Greek krinein, to separate or secrete.