cell-cell contact zone

Definition

Target type: cellularcomponent

Extended zone of intimate apposition between two cells containing one or more types of intercellular junctions, e.g., the intercalated disk of muscle. [NIF_Subcellular:sao1299635018]

Cell-cell contact zones are specialized regions of the plasma membrane where two cells physically interact. These zones play crucial roles in a wide variety of cellular processes, including cell adhesion, communication, and tissue development. They are characterized by the presence of specific transmembrane proteins, adhesion molecules, and signaling molecules that mediate these functions.

The cellular component of cell-cell contact zones can be broadly divided into two main categories:

**1. Adhesion Junctions:** These junctions provide mechanical strength and stability to cell-cell interactions. They are further classified into several subtypes:

- **Tight junctions (TJs):** These junctions form a seal between adjacent cells, preventing the leakage of molecules and fluids between them. They are composed of transmembrane proteins such as occludin and claudins, which interact with scaffolding proteins and adaptor molecules to create a tight barrier.

- **Adherens junctions (AJs):** These junctions are characterized by the presence of cadherin molecules, transmembrane proteins that bind to each other in a calcium-dependent manner. Cadherins interact with intracellular proteins such as catenins, which link them to the actin cytoskeleton, providing mechanical strength and stability.

- **Desmosomes:** These junctions are similar to AJs but are characterized by the presence of desmosomal cadherins, such as desmoglein and desmocollin. They are connected to intermediate filaments, providing even greater strength and stability.

**2. Communication Junctions:** These junctions facilitate communication between adjacent cells. The primary type of communication junction is:

- **Gap junctions:** These junctions form channels between adjacent cells, allowing the passage of small molecules, ions, and signaling molecules. They are composed of connexin proteins, which assemble into hexameric structures called connexons. Two connexons from adjacent cells align to form a gap junction channel.

**Beyond these main components, cell-cell contact zones can also contain other cellular components, such as:**

- **Extracellular matrix (ECM) molecules:** These molecules, such as laminin and collagen, can interact with cell-cell contact zones, providing additional structural support and influencing cell behavior.

- **Signaling molecules:** A variety of signaling molecules, such as growth factors and cytokines, can localize to cell-cell contact zones, playing crucial roles in cell-cell communication and signaling pathways.

In summary, the cellular component of cell-cell contact zones is a complex and dynamic structure that plays essential roles in maintaining tissue integrity, coordinating cell behavior, and facilitating communication between cells.'
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Proteins (1)

Compounds (1)