Written by the Fiveable Content Team • Last updated August 2025
Written by the Fiveable Content Team • Last updated August 2025
Definition
Intracellular signaling is the process by which cells respond to external signals through a series of molecular events. These signals are transmitted within the cell, leading to various cellular responses and activities.
Intracellular signaling often involves the activation of specific proteins such as kinases and phosphatases.
Second messengers like cAMP, Ca2+, and IP3 play crucial roles in amplifying and distributing the signal within the cell.
The process can be divided into three main stages: reception, transduction, and response.
Signaling pathways can lead to changes in gene expression, enzyme activity, or cellular behavior such as growth or apoptosis.
Dysregulation of intracellular signaling pathways can contribute to diseases such as cancer and diabetes.
Related terms
Signal Transduction Pathway: A series of molecular events initiated by a signal molecule binding to its receptor that leads to a specific cellular response.
Second Messenger: Small molecules that propagate a signal within the cell after activation by an initial receptor-ligand interaction.
Kinase: An enzyme that catalyzes the transfer of phosphate groups from high-energy donor molecules, like ATP, to specific substrates.