Autocrine signalling

Autocrine signalling is a form of cell signalling in which a cell secretes a hormone or chemical messenger (called an autocrine agent) that binds to autocrine receptors on the same cell, leading to changes in the cell. This type of signalling is important in many physiological and pathological processes, including cell growth, cell differentiation, and cancer development.

Overview

In autocrine signalling, the target of the signal is the cell itself. This is in contrast to other types of cell signalling such as paracrine signalling, where the target is nearby cells, and endocrine signalling, where the target cells are distant. Autocrine signals often act as a regulatory mechanism for cells that are in a rapidly changing environment and need a quick method of self-regulation.

Mechanism

The mechanism of autocrine signalling involves several key steps:

1. A cell produces an autocrine agent.
2. The autocrine agent is secreted and then binds to receptors located on the surface of the same cell.
3. This binding activates a signal transduction pathway within the cell.
4. The signal transduction leads to a cellular response, such as changes in gene expression or activation of certain cellular functions.

Functions

Autocrine signalling has various functions in different types of cells:

• In the immune system, autocrine signalling can regulate the proliferation and activity of immune cells.
• In cancer cells, autocrine signalling can promote cell survival and proliferation, contributing to tumor growth and progression.
• In stem cells, autocrine signals can influence stem cell maintenance and differentiation.

Examples

A well-known example of autocrine signalling is the action of growth factors such as Epidermal Growth Factor (EGF) and Transforming Growth Factor-alpha (TGF-alpha), which can bind to their own cell’s receptors and stimulate cell growth and division.

Clinical Relevance

Understanding autocrine signalling pathways has significant implications for the development of therapeutic strategies in various diseases, particularly cancer. Targeting autocrine loops with specific inhibitors can potentially disrupt pathological cell growth and survival.

See Also

• Cell communication
• Molecular biology
• Signal transduction