BIO 302 Lecture Notes - Lecture 5: Cell Adhesion Molecule, Basal Lamina, Cell Adhesion
Chapter 12
Cells environment
• Extracellular matrix (mesenchyme)
o Any Tissue outside of cells themselves
o Looser ECM
o
• Basal Membrane ( epithelium )
o Cell-Cell junctions (locked together) ( Not cell type specific ; universal )
o Cell adhesion molecules ( specific to particular cell types )
o Basal membrane/ basal lamina
o
What kind of cell might have to send long projections out through the extracellular matrix?
• A: Nerve cells
Major ECM molecules
• Collagen -lots of types
o MAde up of multiple polypeptide proteins
▪ Self assemble into fibers
• Protein fibers processed by cleaving off the ends.
• Fibronectin - assoc. With collagen
If a cell is leaving the epithelium to migrate, what needs to change to allow that?
• A: Basal lamina would have to go away, or an opening would have to be made.
How are cells ties to the ECM?
• Molecules called integrin proteins tie cells to the ECM and to the cytoskeleton which
allows the whole cell to hold together.
o Transmembrane protein
o
Why would the cytoskeleton need to be tied to the ECM?
• Make a tissue tougher
• Hold cells in place
• Enable cells to pull themselves through a tissue
o What the cells use to move on , grab onto cytoskeleton
Gags( found in high concentrations in cartilage)
• Combine with proteins
o Proteoglycans
1. ECM - tie cells to ECM integrins
2. Cell-cell junctions
a. Tight
b. Goup
c. Desmosomes
i. Note: non-specific can be in lots of different cell types
3. Cell adhesion molecules (CAMs)
. Specific to different cell types- ex. Nerves + epidermis have different CAMs
Sorting out phenomenon; alternative hypothesis
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Document Summary
What kind of cell might have to send long projections out through the extracellular matrix: a: nerve cells. Major ecm molecules: collagen -lots of types, made up of multiple polypeptide proteins, self assemble into fibers, protein fibers processed by cleaving off the ends, fibronectin - assoc. If a cell is leaving the epithelium to migrate, what needs to change to allow that: a: basal lamina would have to go away, or an opening would have to be made. How are cells ties to the ecm: molecules called integrin proteins tie cells to the ecm and to the cytoskeleton which allows the whole cell to hold together, transmembrane protein. Why would the cytoskeleton need to be tied to the ecm: make a tissue tougher, hold cells in place, enable cells to pull themselves through a tissue, what the cells use to move on , grab onto cytoskeleton.
