- What part of an epithelial cell interacts the outside world?: apical region
- What part of an epithelial cell interacts with the internal world?: basolateral region
- What is the Basal lamina/basement membrane?: ECM that holds together epithelial cells
- What type of tissue has looser organization?: connective tissue
- The amount and type of ______ on cell surfaces help segregate cells into specific tissues: cadherins
- What type of adhesive junction interacts with actin?: Adherens junction
- What is an Adherens junction?: cadherin-mediated junctions that interact with actin
- How does the EMT work?: breakdown of epithelium into loosely organized mesenchyme cells from reduced cadherin expression
- _____ occurs in cancer cell metastasis: EMT
- What type of cells have abundant desmosomes?: cells that undergo mechanical stress, like skin, heart, and uterus
- What is the function of desmosomes?: provide structural integrity
- What happens if there is a mutation/decreased expression of desmosomes?: disease of heart and skin
- What type of tissue are hemidesmosomes found in?: epithelial cells
- What do the integrins and hemidesmosomes attach to?: keratin (intermediate filaments)
- What type of protein in hemidesmosomes form a dense plaque that connect integrins to the cytoskeleton?: linker proteins
- What is the function of tight junctions?: seals cells to prevent leakage, helps polarize cells
- What type of junction maintains the apical and basal parts of the cell?: tight junctions
- What are the important proteins of tight junctions?: occludin and claudin
- What is the function of gap junctions?: forms channels that allow small, intracellular water soluble molecules
- What are connexons?: hollow cylinders of 6 connexins that form a hydrophilic channel
- What are the three classes of molecules that make up the ECM?: 1. Structural proteins that provide strength and flexibility (collagen, elastin) 2. Proteoglycans that make matrix 3. Adhesive glycoproteins that allow cells to attach to matrix (fibronectins, lamins)
- What is the structure of collagen?: rigid a triple helix of intertwined polypeptides
- What is the first step in collagen formation?: ER lumen forms a triple helix (procollagen)
- What is the second step in collagen formation?: After secretion out of cell, non helical ends get cleaved by procollagen peptidase
- What is the final step in collagen formation?: collagen molecules form fibrils and then fibers
- What feature does elastin provide to the ECM?: Elasticity
- What amino acids are elastin rich in?: glycine and proline
- What are proteoglycans?: glycoproteins with a lot of glycosaminoglycans attached to one proteins that makes the matrix
- What is imbedded in the gel-like network of proteoglycans?: collagen and elastin
- What are glycosaminoglycans?: large carbs with repeating disaccharide units
- Where are the core polypeptides of proteoglycans embedded?: plasma membrane
- What anchors cells to the ECM?: adhesive glycoproteins
- What is fibronectin?: glycoproteins in the ECM
- Can fibronectins be soluble or insoluble?: yes
- What types of cells have overexpressed fibronectins?: tumor metastasis
- What cellular/body functions does fibronectin help with?: movement and clotting (soluble version)
- What are integrins?: cell surface receptors that bind to fibronectins or lamins
- What are integrins made of?: two large transmembrane polypeptides (Alpha and beta)
- What is anchorage dependent growth?: most cells must be attached to a substrate to grow
- What happens to growth if cells cannot attach?: they stop dividing
- What are focal adhesion?: a type of cell to ECM adhesion
- What links cells to ECM?: integrins