Wnt signaling pathway

Wnt signaling pathway is a group of signal transduction pathways made of proteins that pass signals into a cell through cell surface receptors. These pathways are critically important to the regulation of cell fate, proliferation, migration, polarity, and death, particularly during embryonic development.

Overview

The Wnt signaling pathway is named after its key player, the Wnt protein, a signaling molecule. Wnt proteins bind to receptor proteins of the Frizzled and LRP families on the cell surface. This binding initiates a signaling cascade within the cell that leads to various outcomes, such as cell fate specification, cell proliferation, and cell migration, depending on the cellular context.

Pathway Components

The Wnt signaling pathway is composed of several key components, including:

• Wnt protein: The signaling molecule that initiates the pathway.
• Frizzled: A family of G protein-coupled receptor proteins that serve as receptors for Wnt proteins.
• LRP (Low-density lipoprotein receptor-related protein): Co-receptors for Wnt proteins.
• Dishevelled: A family of proteins that are phosphorylated and activated upon Wnt binding to Frizzled and LRP.
• Beta-catenin: A protein that accumulates in the cytoplasm and then translocates to the nucleus to activate transcription of target genes when the Wnt signaling pathway is activated.

Pathway Types

There are three main types of Wnt signaling pathways:

• Canonical Wnt pathway: Also known as the Wnt/β-catenin pathway, this pathway leads to regulation of gene transcription.
• Non-canonical Wnt pathway: These pathways operate independently of β-catenin. They include the Wnt/Planar Cell Polarity pathway and the Wnt/Ca2+ pathway.
• Wnt/Ca2+ pathway: This pathway leads to release of intracellular calcium, which can activate several different intracellular enzymes.

Role in Disease

Abnormal Wnt signaling is implicated in a number of diseases, including cancer, birth defects, and neurodegenerative diseases. For example, mutations that lead to overactive Wnt signaling have been found in many types of cancer, including colorectal, breast, and lung cancers.

See Also

• Signal transduction
• Cell signaling
• Cancer
• Neurodegenerative diseases