What is the name given to the protein that mediates changes inside a cell during signaling?

The term for the protein that mediates cellular changes during signaling is effector protein. These proteins play a crucial role in transducing signals received by receptors on the cell surface to initiate cellular responses. Once a receptor protein binds to a signaling molecule (like a hormone or neurotransmitter), it activates effector proteins within the cell, leading to various physiological responses.

Effector proteins can include enzymes that alter biochemical processes, cytoskeletal proteins that change cell shape, or transcription factors that regulate gene expression. The activation of these proteins represents the final step in the signal transduction pathway, resulting in the appropriate response dictated by the initial signal. This understanding of effector proteins is essential for elucidating how cells respond to their environment, making them critical components of cellular biology and signaling mechanisms.