Seminar Date: Wednesday 22nd November
Time: 12pm – 1pm
Module: Cell Biology BI503
Cell Junctions and Extra Cellular Matrix (ECM)
The video on the introductory slide shows the formation of the layer of cells which form a
hexagonal pathway. This pathway creates a connection between cells and forms an extra
cellular matrix.
The second the cell touches another cell this forms cell adhesion, which holds the cells in
place. Today we are going to discuss an overview of cell adhesion and the research at Kent
in mechanical computation of cells and how they are using adhesions to store and calculate
how to behave.
Picture of molecular biology of the cell.
1) Cell deep – held on to each other by cell junctions and connect to the basal lamina
through cell basal junctions. The layer of cells, basal lamina, is built of a meshwork of
proteins which the cells latch on to.
2) Connective tissue (collagen) - besides each cell you have connective tissue holding
them together. This can bare mechanical stress and compression. There are other
types of cells called fibroblast which ensure ECM stays exactly how the body wants.
If you want to hold something, you need all the cell junctions, coupling to the microtubules,
and actin cytoskeleton.
Two sub classes mediated in cell space and making links to the ECM are:
1) Basal membrane– ECM at the bottom and the cells sit on top of that.
2) Interstitial matrix – affects the mechanical properties of cells and facilitates the
transport of nutrients.
Image shows the cytoskeleton with red lines to denote actin cytoskeleton and blue to denote
intermediate filament cytoskeleton.
1) The ECM is made up of:
2) Tight junctions - tight making waterproof boundary.
3) Adherens junctions
4) Desmosome- connect to intermediate filaments between adjacent cells holding
structure together.
5) Gap junctions- junction between two cells with pore in the middle so electrolytes can
travel through. This is a size barrier.
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