Cell Signals That Use Second Messengers

Cell signals often use second messengers to carry messages inside the cell. Many receptor-binding ligands are hydrophilic, so they do not cross the cell membrane. Instead, the signal is relayed to an internal messenger that can spread the message farther.

G-protein coupled receptors can activate ...

Cell signaling begins when signaling molecules called first messengers, such as hormones, bind to receptors on the cell surface. Next, small intracellular, non-protein molecules relay and amplify the signals received at the cell surface. These molecules are called second messengers.

One important signaling pathway that uses second messenge...