What is the name of the protein that transmits signals in a signaling pathway?

In a signaling pathway, the protein responsible for transmitting signals is known as a relay protein. These proteins play a crucial role in the cascade of communication that occurs in response to external signals, such as hormones or growth factors. When a molecule binds to a receptor on the surface of a cell, it often triggers a series of events inside the cell, involving several proteins that relay the signal from the receptor to various targets within the cell. This relay mechanism is essential for amplifying and propagating the original signal so that the appropriate cellular response can be initiated.

The importance of relay proteins lies in their ability to interface between the receptor proteins, which detect the signal, and other proteins that might mediate a response, such as enzymes that might catalyze a reaction or transcription factors that activate gene expression. Relay proteins can be involved in various processes, including phosphorylation cascades, which are crucial for cell signaling.

In contrast, receptor proteins are specific for the initial binding of signaling molecules, while structural proteins primarily provide support or shape to cells and tissues, and enzymes typically catalyze biochemical reactions rather than directly transmitting signals.