Cell Adhesion and Extracellular Matrix Flashcards
What is connective tissue composed of?
cells (scattered)
Extracellular matrix
-fibrillar proteins
-hydrated gel of GAGs
Name me some Fibrillar proteins found in the extra cellular matrix
collagen
elastin
fibronectin
laminin
Name a vesicle that transports proteins from the RER to the Golgi
COPII buds
Tell me about the secretion of collagen
occurs by exocytosis at specialised sites
what is the production of collagen fibril by fibroblasts in a membrane tube called
fibripositor
elastic recoil is what kind of effect
hydrophobic
What do proteoglycans provide
matrix support/cushioning/hydration
glue-like function
Links between proteins of ECM and ECM and cell surface
what are GAGS
Long chains of repeating disaccharide units highly charged (-ve) and highly hydrated
The binding
Extracellular = collagen, fibronectin, proteoglycans
plasma membrane = integrin
intracellular = actin and adapter protein
What are the two functions of a myofibroblast
secrete collagen
smooth muscle like synthesise actin myosin and desmin
What do myofibroblasts do in response to tissue damage
proliferate
secrete collagen as a scaffold
consolidate damaged area - fibrous scar
contract (reduce size of damaged area)
What is the composition of mast cells in terms of granules
heparin
histamine
desmosome
intermediate filaments
adhernens junction
actin filaments
What does plaque contain
desmoplakin
plakoglobin
Cadherins
a type of cell adhesion molecule (CAM) that is important in the formation of adherens junctions to bind cells with each other
what’s the role of focal adhesions
link the outside of the cell (ECM) through transmembrane proteins (interns) with cytoskeleton (actin filaments)
-signalling platforms
hemidesmosomes
the same except intermediate filaments and they are more stable
interns
bridges between cyctol and ECM
Duchenne muscular dystrophy
gene mutation absence of dystrophin (adapter) due to premature termination of translation
PTC 124 (ataluren)
experimental drug which overrides the premature stop signal mutation to produce normal dystrophin
E-cadherin
epithelia
N-cadherin
neurons and heart muscle
P-cadherins
placenta, epidermis
VE-cadherin
endothelial
Cell adhesion in cancer stages
tumour cells accumulate
carcinoma arriving
cells undergo mesenchymal transition (losing cell adhesion)
Microinvasion
- cells convert to “mesenchymal” cells and expression of cadherins reduced
- aided by actin based protrusions (invadipodia)
- basement membrane breached
- in invading tumours leading cells express integrins promoting interaction with ECM and non-epithelial cells during movement
