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Cell bio 2 wks ago
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Cell bio 2 wks ago
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Multiadhesive Glycoproteins
Proteins in the ECM that promote cell adhesion.
Ground Substance
A component of the ECM containing primarily glycosaminoglycans (GAGs), proteoglycans, and glycoproteins.
Extracellular Matrix (ECM)
The organized meshwork of macromolecules surrounding and underlying cells.
Fibers
Structural components of the ECM that vary in composition.
Composition of ECM
Varies in composition, containing ground substance, multiadhesive glycoproteins, and fibers.
Extracellular Environment
Includes the ECM, water, and other small molecules, constituting the environment outside the cells.
Metabolic Activities
The activities of cells that can be affected by the ECM.
Cell-ECM Interactions
The influence of the ECM on the shape, migration, and interactions of cells.
Cell Differentiation
The process influenced by the ECM, leading to cells taking on specialized functions.
Physical Support
Provided by the ECM against compressive and tensile forces.
ECM Function
Affects cell metabolism, shape, migration, interactions, division, and differentiation, while also providing physical support.
What is the watery largely unstained extracellular material rich in hydrated glycosaminoglycans?
Ground substance (the extracellular matrix, ECM)
What are Glycosaminoglycans (GAGs)?
They are a family of unbranched polysaccharide chains of repeating disaccharide units with multiple negative charges that constitute a large volume fraction of the ECM.
What is the structure of Glycosaminoglycans (GAGs)?
They are a polymer of repeating disaccharide units.
What is the function of Glycosaminoglycans (GAGs)?
They bind H2O in connective tissue due to their negative charges and act as a cushion, allowing tissue to temporarily adapt its shape under externally applied stress and then return to its original state.
Proteoglycans
Proteins with numerous covalently linked GAG side chains
Proteoglycans Function
Bind H2O, shock absorption, supportive function (e.g., in cartilage), resistance to compression of articular cartilage, formation of cell-cell junction or cell-matrix junction, signaling and regulatory functions (e.g., by binding signaling molecules)
Ground Substance
The extracellular matrix (ECM)
Glycoproteins
Proteins with short carbohydrate side chains that contribute to the organization of the extracellular matrix by offering specific binding sites for cells and other matrix molecules
Glycoproteins Examples
Fibronectin, Laminin
Fibronectin
Glycoprotein important for cell-matrix interactions, binds to collagen and integrins, plays an important role in embryogenesis, regulates cell migration and hemostasis, crosslinking of fibrin molecules with thrombocytes and fibroblasts
Laminin
Major component and organizer of the basal lamina besides type IV collagen, binds to collagens, integrins, and proteoglycans
What is the repeating amino acid sequence in a collagen molecule?
GlyXYn
What is the first amino acid of the GlyXYn triplet in the collagen molecule?
Glycine
What is the most common amino acid in position X of the GlyXYn triplet in the collagen molecule?
Proline
What is commonly found in position Y of the GlyXYn triplet in the collagen molecule?
Hydroxyproline or hydroxylysine
What is the function of collagen in the body?
To organize, strengthen, and provide elasticity to the extracellular matrix
How many types of collagen triple helices can be assembled from the 42 genes coding for collagen chains?
28 types
Where does the modification of the polypeptide chain of collagens occur during collagen synthesis?
Rough endoplasmic reticulum (ER)
These very large molecules are enclosed in vesicles, transported to the cell membrane via the Golgi apparatus, and secreted via exocytosis in the extracellular space.
Collagen synthesis.
