Dunn M&C Cell Interactions

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basement membrane / basal lamina

most abundant types of animal cell ECM; underlies epithelial tissue and interstitial matrix of connective tissue

extracellular matrix (ECM)

A complex network usually of proteins and carbohydrates that provides structural and biochemical support to surrounding cells; influences cell shape and gene expression

• experimentally what is left lover after you decellularize a tissue

• most ECM molecules have glycoproteins (protein and carb components)

interstitial matrix of connective tissue

makes up the bulk of connective tissue

epithelial tissue

solid cells; interacting w/ one another

connective tissue

cells are not interacting on all sides w/ each other; dispersed

characterized by sparse cells and substantial amounts of extracellular matrix (ECM)

collagen

abundant ECM protein

fibroblasts

the primary cells responsible for producing and maintaining the extracellular matrix (ECM) in connective tissues

skin layers

epidermis and dermis

epidermis

several cell layers thick and is an epithelial tissue — here mainly keratinocytes (IFs) but also melanocytes

dermis

mostly made up of connective tissue

• also contains the nerve endings and blood vessels

• strong and flexible

• the main cell type found here is fibroblasts, which synthesize the extracellular matrix and repair wounds

animal cell ECM

in animals; made up of proteins, glycoproteins, and carbohydrates that provide structural and biochemical support to surrounding cells.

integrins

transmembrane receptors that facilitate cell-ECM adhesion, allowing cells to bind to the extracellular matrix and communicate with their environment.

• used in adhesion junctions

cadherin

integral membrane protein that play a crucial role in cell adhesion, helping cells stick together and communicate

• attaches to the cytoskeletal proteins on the cells interior which couples a cell’s skeleton to its neighbor’s

• used in adhesion junctions

adhesion junctions

cells need to stick to one another and to ECM to form/maintain tissue

occluding junctions

prevent passage of hydrophilic solutes from one side of cell layer to the other (“ziploc”); prevents food in the gut form passing into the surrounding tissue; prevents apical PM proteins from diffusing to the basolateral membrane

• cells with junctions aresealed together, maintaining compartmentalization.

channel-forming junctions

sharing small molecules in the cytosol; makes cell-signaling faster so that cells in a tissue can coordinate their activity temporally

tight junction

occluding junction; seals cells together like ziplock to create a barrier

desmosomes

adhesive intercellular junctions that strengthen tissues by linking the intermediate filament cytoskeletons of adjacent cell

gap junctions

channel-forming junctions; acts as channels between cells allowing direct communication and exchange of small molecules.

plant cell wall

extracellular matrix of plant tissues; made up of different types of carbohydrate polymers (nitrogen (needed for proteins) is scarce)

cellulose

tensile strength (resistance to pulling) in plant cell walls, providing structure and support.

keratinocytes

primary cell type found in the epidermis, making up about 90% of its cellular content. They are responsible for forming the protective barrier of the skin by producing keratin, a fibrous protein that provides strength and water resistance

melanocytes

specialized skin cells located primarily in the basal layer of the epidermis. They are responsible for the production of melanin, the pigment that gives skin, hair, and eyes their color