Term
Describe the ECM
1. Functions
2. Locations
3. Protein distribution |
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Definition
1. support, holds cells together, communication
2. Connective: lots of ECM
RBC: no ECM
3. different matrices have different kinds of proteins
Tendons: fibrous proteins
Cartilage: polysaccharides
-form compression gel |
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Term
| Describe Chondroitinsulfate chains |
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Definition
Proteoglycan
-sugar chains link to protein
-chains shrink over time
Long chain>more water>more squishy>more resistant to compression
-younger people have better joints |
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Term
Describe Collagen
1. Structure
2. Function |
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Definition
*most abundant protein in animal tissues
1. 3 collagens form triple helices (phone cord)
-helix consists of Gly-X(Proline)-Y(Hydroxypro) repeats
Gly: allows protein to pack tightly
X and Y: stabilize by forming hydrogen bonds
Hydroxyproline- synthesized in ER
2. Strength and Structure
-tight and strong |
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Term
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Definition
*most abundant collagen
-polypeptide chains have 330 Gly-X-Y repeats
-after secretion, they are cleaved and form fibrils
-fibrils form in staggered array
-cross linked by lysine and hydroxylysine
-fibrils form collagen fibers |
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Term
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Definition
Found in basal laminae
-does not form fibrils
-non helical domains combine to form anchoring domains
-link basal laminae to underlying connective tissue |
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Term
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Definition
-elastic fibers that cross link to form network
-common in the lungs
-strong under tension but snap back when released |
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Term
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Definition
Glycosaminoglycans
-repeating units of disaccharides
1. N-glucose or N-galactose
2. glucoronic or iduronic acid
-addition of sulfate group to N-gluc/galact make GAGs negatively charged
-bind to water and trap water to form hydrated gels |
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Term
Describe the following GAGs
1. Hyaluronan
2. Dematan sulfate
3. Chondroitin sulfate
4. Keratan sulfate
5. Heparan sulfate |
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Definition
1. Gluc acid + N-glucos
2. Id acid + N-galact
3. Gluc acid + N-galact
4. Galactose + N-gluc
5. Id acid + N-gluc |
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Term
Describe Proteoglycans
1. Hyaluronan
2. Aggrecan
3. Chondroitin |
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Definition
GAGs link with proteins to form proteoglycans
1. only GAG that doesn't bind proteins is Hyaluronan
-single long poly saccharide
-synthesized at plasma membrane
-interacts with proteoglycans to form large complexes
2. Aggrecan- major proteoglycan in cartilage
-100 chains of chondroitn attached to protein
-aggrecan associate with hyaluronan that become trapped in collagen network
3. neurons can't grow in chondroitin sulfate |
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Term
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Definition
main adhesion protein of connective tissues
-cross linked to collage fibrils
-recognized by integrins and attaches cells to ECM
-contains binding sites for:
1. GAGs (proteoglycans)
2. integrin - RGD residues
3. collagen |
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Term
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Definition
form networks that are major structure of basal laminae
-synthesized in early embryos (no collagen)
-3 chains that form a cross
binding sites for:
1. collagen- type IV
2. cell surface receptors
3. GAGs
4. Entactin- also binds to IV collagen |
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Term
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Definition
cell surface receptors that attach cells to ECM
-transmembrane proteins that bind to:
a. collagen b. fibronectin c. laminin
-signal promotes second messenger |
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Term
Describe the cell matrix junctions
1. Focal adhesions
2. Hemidesmosomes
3. Gap junctions |
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Definition
1. bundles of actin anchored to beta integrin via alpha actinin, talin, and vinculin
2. anchor epithelial cells to basal lamina
-integrins bind to laminins
3. pores in membranes to transfer contents
-high Ca closes junction |
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Term
Describe Cell adhesion
1. Selectins |
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Definition
1. mediate interactions between WBCs and endothelial cells
-selectins on WBCs recognize carbohydrates on endothelials
1. mediate initial adhesion
2. more stable adhesions form when integrins on WBCs bind to ICAMs on endothelial |
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Term
Describe Cell adhesion
1. Ig superfamily
2. Cadherins |
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Definition
1. similar to antibodies
-ICAMs bind to integrin (heterophilic interaction)
-homophilic: N-CAMs nerve cells in development |
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Term
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Definition
mediate homophilic interatcions
E-cadherin on epithelial cells leads to selective adhesion of other epithelial cells |
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