Cell-to-cell junctions Michaela Tiffany

Cell-to-cell junctions

Michaela Tiffany

Surface markers

Structure: Variable, integral proteins or glycolipids in plasma membrane

Function: Identify the cell

Example: MHC complexes, blood groups, antibodies

Septate junctions/tight junctions

Structure: Tightly bound,

leakproof

, fibrous claudin protein seal that surrounds the cell

Function: Holds cells together such that materials pass through not between the cells

Example: Junctions between epithelial cells in the gut

Adhesive junction (Desmosome)

Structure: Variant

cadherins

, desmocollins, blind to intermediate filaments of cytoskeleton

Function: Creates strong flexible connections between cells

Found in vertebrates

Example: Epithelium

Adhesive junction(Adherens junctions)

Structure: Classical

cadherins

, bind to microfilaments of cytoskeletonFunction: Connects cells together

Oldest form of cell junction

Found in all multicellular organisms

Example: Tissues with high mechanical stress, such as the skin

Adhesive junction (

Hemidesmosome

, focal adhesion)

Structure: Integrin proteins bind cell to extracellular matrix

Function: Provide attachment to a substrate

Example: Involved in cell movement and important during development

Communicating junction (Gap junction)

Structure: Six transmembrane connexons/pannexin proteins creating a pore that connects cells

Function: Allows passage of small molecules from cell to cell in a tissue

Example: Excitable tissue such as heart muscle

Communicating junction (Plasmodesmata)

Structure: Cytoplasmic connections between gaps in adjoining plant cell walls

Function: Communicating junctions between plant cells

Example: Plant tissues

All information in this power point can be found in

Mgraw

Hill Biology 10th Edition on pages

82-85