Cellular Biology I: Cell Interactions

Cell junctions that allow cells to attach to the extracellular matrix (ECM).

Specialized structures where cells adhere to the ECM, acting as communication points.

These are sites where cells form connections with the ECM and send signals.

FAs play a key role in cell locomotion, allowing cells to move around by interacting with the environment.

FAs are large, complex structures that function to transmit forces and signals between the ECM and the cell.

Integrins, a type of protein, play a crucial role in FAs. They dynamically interact with the ECM and transduce signals inside the cell.

Actin filaments in the cell contract, causing movement in response to signals received from the ECM via FAs.

FAs are dynamic structures, constantly forming and reforming, allowing for adaptability and movement.

Protein that connects the ECM to the cytoskeleton.

The process of forming a focal adhesion.

A type of protein that helps link integrins to the cytoskeleton, facilitating a strong connection.

The ability of cells to pull themselves along surfaces, driven by forces generated within the cell.

The attachment of integrin to an ECM ligand triggers a chain reaction of signaling events within the cell.

A conformational change in talin exposes binding sites for actin, initiating actin binding and activation.

Specialized structures that attach cells to the basement membrane, a type of ECM particularly important for epithelial cells.

A transmembrane protein found in basal keratinocytes, crucial for connecting the cell to the basement membrane.

The space between the basal keratinocytes and the basement membrane, where integrin connects to the basement membrane.

A group of autoimmune skin diseases characterized by blistering and separation of skin layers, often caused by malfunctions in hemidesmosomes.

A rare genetic skin disorder that affects hemidesmosomes, leading to widespread blistering and skin fragility.

A type of cell junction that forms a strong seal between adjacent cells, preventing leakage of fluids and molecules.

A type of cell junction that provides structural support and adhesion between cells, acting as a 'spot weld' or 'button' between them.

A type of cell junction that allows the exchange of small molecules and allows cells to communicate directly with each other.

A type of cell junction that forms strong connections between cells, ensuring the stability and integrity of tissues.

A family of transmembrane proteins that mediate cell-cell adhesion, crucial for tissue formation and development.

A group of proteins that bind to cadherins, linking them to the cytoskeleton and regulating cell signaling.

A large family of proteins involved in cell-cell adhesion, including desmogleins and desmocollins, found in desmosomes and adherens junctions.

Tight junctions are multiprotein junctional complexes that create a seal between adjacent epithelial cells. They act as a barrier to the free diffusion of water and solutes, preventing them from passing between cells (paracellular pathway). They also serve as a fence to maintain cell polarity, ensuring that different parts of the cell have distinct functions.

Occludin is a protein that forms tight junctions. It has four transmembrane domains, with both its N-terminus and C-terminus located inside the cell. It forms two extracellular loops and one intracellular loop, which play a role in regulating the permeability of the paracellular space.

Claudins are a family of proteins that are essential for tight junction formation. They have four transmembrane domains and a similar loop structure to occludin. Claudins provide the backbone of tight junctions and play a crucial role in sealing the paracellular space, controlling what can pass between cells.

Gap junctions are specialized sites of communication between animal cells. They connect the cytoplasms of neighboring cells by forming channels called connexons. Connexons are made up of integral proteins called connexins.

Gap junctions allow the passage of small molecules and ions between cells, facilitating rapid communication and coordination. In the heart, gap junctions help synchronize the contraction of cardiac muscle cells, ensuring efficient blood pumping.

A type of cell junction that forms a belt-like structure encircling cells within an epithelium, allowing for strong adhesion and maintaining tissue integrity.

Cadherins are proteins that mediate cell-cell adhesion in zonula adherens. They specifically interact with identical cadherins on neighboring cells, creating a strong bond.

Catenins are a family of proteins that link cadherins to the actin cytoskeleton, transmitting forces and enabling cell-cell adhesion. They also play a role in signaling pathways.

A type of cell junction that forms strong, disc-shaped attachments between adjacent cells, providing structural support and resisting mechanical stress.

Desmosomes are found in tissues that experience significant mechanical stress, such as the heart muscle, bladder, and skin, where they provide strength and integrity.

Desmogleins and desmocollins are specific cadherin subtypes involved in desmosomes. They interact heterophilically, meaning they bind to different cadherin subtypes on neighboring cells.

Desmosomal cadherins connect to intermediate filaments within the cell via a network of linker proteins, creating the 'desmosome-intermediate filament complex' (DIFC).

Desmosomes are crucial for maintaining tissue integrity by linking cells together to form strong and resilient structures.

Zonula adherens form belt-like junctions, while macula adherens form disc-shaped junctions. Both are essential for cell-cell adhesion and maintain tissue structure.

By linking cells together, cell junctions like zonula adherens and macula adherens contribute to tissue integrity and prevent cell detachment. They also play a role in signaling pathways.