BIOL2200 Lecture Notes - Lecture 8: Immune System, Cytoskeleton, Endothelium
CYTOSKELETON LEC 5 BIOL2200
Lecture 4: cell-cell and cell-matrix adhesions
Cell adhesions and interactions
Two main categories of cellular adhesive interactions:
oCell-matrix interactions
oCell-cell interactions
Both are mediated by a specific class of molecules:
oCell adhesion molecules (CAMs)
Two main ways in which animal cells are bound together
Transmembrane adhesion proteins link the cytoskeleton to extracellular structures
Cell-matrix interactions
oThe extracellular matrix is essential for regulated development and function of
multicellular organisms
oPrimary components of the ECM:
Proteoglycans
Collagen (s)
Laminin primary molecule in basement membranes
Fibronectin found in most extracellular matrix structures
oNormal cells make lots of fibronectin as a matrix many cancer cells are defective in
making extracellular matrix
Normal cells
Cancer cells good correlation between loss of extracellular matrix and
cancer
oFibronectin and collagen are essential for embryonic development
Antibodies (blocked) against fibronectin morphogenesis of salivary glands
Deletion of collagen-II gene results in dwarfism either lethal or will have a
defect
oCells interact with the ECM via specific receptors
The receptors for fibronectin, collagen and many other ECM components
belong to a family of molecules called integrins. These occur as heterodimers of
different alpha chains and beta chains
oIntegrins have specificity towards different ECM components
Different combination of alpha and beta subunits confer specificity
Integrins link to the actin cytoskeleton
How do cells adhere to ECM components?
oAreas of adhesion where the cell adheres to the ECM:
Adherens Junctions, sometimes called adhesion plaques or focal contacts
Specialised structures. This is where the actin cytoskeleton interacts with
the membrane and is mediated by two other proteins:
vinculin and talin
Vinculin and actin
oLocalisation of vinculin (red) at adheres junctions in cells)
oGreen: actin
Cell-cell adhesions cadherins interact with eachother
Adherens junctions and desmosomes
oHold cells together or to extracellular matrix
Tight junctions
find more resources at oneclass.com
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Document Summary
Two main categories of cellular adhesive interactions: o o. Both are mediated by a specific class of molecules: o. Two main ways in which animal cells are bound together. Transmembrane adhesion proteins link the cytoskeleton to extracellular structures. The extracellular matrix is essential for regulated development and function of multicellular organisms o. Fibronectin found in most extracellular matrix structures: normal cells make lots of fibronectin as a matrix many cancer cells are defective in making extracellular matrix. Cancer cells good correlation between loss of extracellular matrix and cancer o. Fibronectin and collagen are essential for embryonic development. Antibodies (blocked) against fibronectin morphogenesis of salivary glands. Deletion of collagen-ii gene results in dwarfism either lethal or will have a defect o. Cells interact with the ecm via specific receptors. The receptors for fibronectin, collagen and many other ecm components belong to a family of molecules called integrins. These occur as heterodimers of different alpha chains and beta chains o.
