Cell Adhesion and Signalling Overview

Inflammation regulates selectins. E-selectin upregulates on blood vessel walls to help neutrophils move out of the blood vessels. P-selectin is expressed on platelets to aid platelet aggregation.

Cell surface proteoglycans that act like adhesion molecules, connecting cells to the extracellular matrix (ECM) and binding growth factors and cytokines.

Anchoring junctions joining epithelial cells to the basement membrane. They use special integrins (α6β4) to connect to laminin in the basement membrane and keratins within the cells

Cell adhesion molecules that connect cells to the extracellular matrix and the intracellular cytoskeleton.

A complex network of proteins and carbohydrates that surrounds cells and supports them.

A family of adhesion proteins that mediate calcium-dependent homophilic adhesion between cells.

Individually low adhesion affinity, but in combination, create strong cell attachment.

Proteins that link classical cadherins to the actin cytoskeleton.

Specialized channels that allow small molecules (e.g., ions, sugars) to pass between cells.

Structures that create a seal between adjacent cells, preventing leakage of molecules.

Cell adhesion molecules whose extracellular domains have multiple immunoglobulin-like domains.

Mediate calcium-independent cell adhesion.

Cell surface carbohydrate-binding proteins (lectins) involved in transient cell-cell adhesion.

Bind to mucin (addressins), glycoproteins on cell surfaces, in calcium-dependent way.

Formation of a synapse requires multiple cell-adhesion molecules.

Control the recruitment of neutrophils to infected tissues via transient and weak interactions.

Allow circulating T cells to home to lymph nodes by binding to vascular endothelium.

Integrin activation is a process where integrins (cell surface proteins) change shape in response to signals, leading to attachment to the extracellular matrix.

The extracellular signal from ligand binding elicits intracellular responses in integrins.

The intracellular signal, triggered by ligands, modifies integrins to increase extracellular binding.

Focal adhesions are strong connections between the integrins and the cytoskeleton through proteins like vinculin.

Specialized adhesion structures involved in cell motility and the focal adhesion complex.

The internal support structure of a cell.

Specific combinations of integrin proteins which allow for unique cell interaction types.

The insoluble extracellular network of structural proteins such as collagen and elastin.

Both are structures involved in cell attachment, but focal adhesions are strong, stable junctions for anchoring cells to the matrix, while podosomes are dynamic, smaller structures involved in cell motility and matrix degradation.

Specific combinations of alpha and beta integrin subunits that allow for unique cell-matrix interactions and functions. Different pairs have different ligand preferences and signaling properties.

A family of cell adhesion proteins that depend on calcium for their function.

Cadherins mediate cell-cell adhesion, forming strong attachments between cells when they interact.

Proteins that connect cadherins to the actin cytoskeleton.

Specialized channels that allow small molecules to pass between cells.

Structures that create a seal between adjacent cells, preventing leakage of molecules.

Cell surface carbohydrate-binding proteins involved in transient cell adhesion.

Selectins help guide neutrophils and other immune cells to the site of inflammation.

A group of cell adhesion molecules with immunoglobulin-like domains.

They mediate calcium-independent cell adhesion, holding cells together without calcium.

They join pre- and post-synaptic membranes, anchoring components of signaling machinery.

Selectins are 'turned on' (upregulated) by inflammatory signals like TNF-alpha. They allow neutrophils to 'roll' along blood vessel walls, getting closer to the infection site.

Syndecans are cell surface molecules (proteoglycans) that help cells connect to the extracellular matrix (ECM).

Syndecans help cells 'talk' to the ECM. They can bind to growth factors and cytokines, which control cell behavior.

Hemidesmosomes are special connections that anchor epithelial cells to the basement membrane.

Hemidesmosomes use a specific type of integrin (alpha6beta4) to link to laminin in the basement membrane and keratins within the epithelial cells.

Integrins are like 'cellular Velcro' - they're adhesion molecules that help cells stick to the ECM.

Integrins have two main parts: one binds to the ECM, the other connects to the cytoskeleton inside the cell. This creates a strong link.

The ECM is a complex network of proteins and carbohydrates that surrounds cells and helps hold them together.

The ECM provides structural support for tissues, helps cells migrate, and plays a role in cell signaling.

The extracellular matrix (ECM) is a complex network of proteins and carbohydrates that surrounds cells and supports them. It serves as a scaffold, providing structural support and serving as a signaling platform.

Cells adhere to each other through specialized junctions, like adherens junctions and desmosomes, which connect the cytoskeletons of adjacent cells. These junctions use cell adhesion molecules (CAMs) like cadherins to provide strong connections.

Cells adhere to the ECM through integrins, which are transmembrane proteins that link the cytoskeleton to the ECM. Integrins can also act as signaling molecules, transmitting information from the ECM to the cell.

There are various types of CAMs. Cadherins are crucial for cell-to-cell adhesion, integrins link cells to the ECM, and selectins mediate transient cell-cell interactions, typically in immune responses.

Cell junctions are essential for maintaining the structural integrity of tissues. They also play crucial roles in tissue development, wound healing, and cell signaling, ensuring coordinated functions between cells within a tissue.

Tight junctions are specialized cell junctions that act as barriers, preventing the leakage of molecules between cells. They are crucial for maintaining the integrity of epithelial tissues, acting as a seal.

Gap junctions are channels that connect the cytoplasm of adjacent cells, allowing the passage of small molecules and ions. They facilitate direct communication between cells, important for coordinated actions like heart muscle contraction.

Cell adhesion plays a critical role in the immune system. Leukocytes (white blood cells) use selectins for transient adhesion to endothelial cells lining blood vessels, allowing them to leave circulation and reach sites of infection.