Juxtacrine signalling

Juxtacrine signalling is a form of cell signaling in which the signaling molecules are located on the surface of cells and interact with receptor molecules on the surface of adjacent cells. This type of signaling requires direct contact between the cells involved. Juxtacrine signaling plays a crucial role in various biological processes, including embryonic development, immune responses, and the maintenance of tissue and organ architecture.

Mechanism

Juxtacrine signaling involves the interaction between signal molecules anchored on the membrane of one cell and receptor molecules on the surface of an adjacent cell. Unlike other types of cell signaling, such as paracrine signaling or endocrine signaling, which involve the release of signaling molecules into the extracellular space or bloodstream, juxtacrine signaling does not require the diffusion of molecules. Instead, it relies on physical contact between cells. This direct mode of communication allows for highly localized and specific responses.

Roles in Biological Processes

Juxtacrine signaling is involved in numerous biological processes:

Embryonic Development

During embryonic development, juxtacrine signaling is essential for the regulation of cell differentiation and tissue formation. It ensures that cells develop into the correct cell types and organize into proper structures by providing spatially restricted signals.

Immune Response

In the immune system, juxtacrine signaling is critical for the activation and regulation of immune cells. For example, the interaction between antigen-presenting cells and T-cells involves juxtacrine communication, which is necessary for the initiation of an adaptive immune response.

Tissue and Organ Architecture

Juxtacrine signaling contributes to the maintenance of tissue and organ architecture by mediating cell adhesion and communication. It helps cells to recognize their neighbors and establish stable tissue structures.

Examples of Juxtacrine Signaling

One well-known example of juxtacrine signaling is the interaction between Notch receptors and their ligands, such as Delta and Jagged, on adjacent cells. This signaling pathway is involved in numerous developmental processes and in the regulation of cell fate decisions.

Another example is the Eph receptor and ephrin ligand system, which plays a significant role in the development of the nervous system and in vascular development.

Clinical Significance

Aberrations in juxtacrine signaling pathways can lead to various diseases, including cancer, autoimmune diseases, and developmental disorders. Understanding the mechanisms of juxtacrine signaling is therefore crucial for the development of therapeutic strategies targeting these pathways.

See Also

• Cell signaling
• Paracrine signaling
• Endocrine signaling
• Notch signaling pathway
• Eph receptor

References

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