58 Questions
What is the main function of the extracellular matrix?
Provides structure and support, holds cells and tissues together
Which proteins are considered major components of the extracellular matrix?
Collagens, elastin, laminin
What are the effects of defects in the production of ECM proteins?
Scurvy, OI, JEB
What are MMPs and TIMPs in the context of ECM?
MMPs are enzymes that degrade ECM components, while TIMPs regulate MMP activity
What is the significance of hydration in the extracellular matrix?
Hydration is important for density and deformability of the matrix
Which of the following is NOT a function of the extracellular matrix?
Promotes movement of materials within the matrix
Which protein is NOT a major component of the extracellular matrix?
Keratin
What is the special form of ECM that is mentioned in the text?
Basal lamina
What is the consequence of defects in the production of ECM proteins such as scurvy, OI, and JEB?
Weakening of connective tissue
What are glycosaminoglycans and proteoglycans primarily responsible for in the extracellular matrix?
Maintaining hydration and resilience
Which enzyme is responsible for converting glucuronic acid to iduronic acid in glycosaminoglycans?
Epimerase
What is the primary role of matrix metalloproteinases (MMPs) in the extracellular matrix?
Migration and remodeling
Which component of the extracellular matrix attaches matrix proteins to integrins on cells?
Fibronectin
What is the source of sulfate added to glycosaminoglycans (GAGs)?
PAPS
What is the role of hyaluronic acid in the extracellular matrix?
Can exist separately
Which protein is responsible for linking the cytoskeleton to the matrix in the extracellular matrix?
Integrins
What can lead to diseases such as mucopolysaccharidoses (MPS) in the context of the extracellular matrix?
Defects in integrins
What is the primary function of glycosaminoglycans (GAGs) in the extracellular matrix?
Side chains on proteoglycans
What are the primary regulators of matrix metalloproteinase (MMP) activity in the extracellular matrix?
Tissue inhibitors of metalloproteinases (TIMPs)
How does matrix degradation primarily occur in the extracellular matrix?
Endocytosis and lysosomal hydrolases
What is the role of proteoglycans in the extracellular matrix?
Linked to serine or threonine
What is the significance of defects in integrins in the extracellular matrix?
Can lead to diseases such as mucopolysaccharidoses (MPS)
Which protein is abundant in elastic fibers and allows blood vessels to deform and lungs to expand and contract without using energy?
Elastin
What is the primary role of lysyl oxidase in the context of collagen?
Crosslinking helices into larger structures
Which vitamin is essential for the stability of collagen and tissues where it is important?
Vitamin C
What is the consequence of a defect in laminin 5 or 6 in the context of the extracellular matrix?
Junctional epidermolysis bullosa
What is the major function of matrix metalloproteinases (MMPs) in the extracellular matrix?
Degradation of extracellular matrix components
What is the primary role of collagen IV in the extracellular matrix?
Meshwork formation in basement membranes
What are the alternating hydrophobic and hydrophilic domains in elastin responsible for?
Stretch-induced reorganization of water
What is the primary function of glycosaminoglycans in the extracellular matrix?
Maintenance of matrix hydration
What is the structure of collagen Type IV in the extracellular matrix?
Mesh-like
What is the consequence of a defect in collagen synthesis that leads to blue sclera?
Osteogenesis Imperfecta
What is the primary role of basal lamina in the extracellular matrix?
Cell attachment
What is the most abundant protein in basal laminae after Type IV Collagen in the extracellular matrix?
Laminin
What is the most abundant protein in basal laminae after Type IV Collagen in the extracellular matrix?
Laminin
What is the primary role of lysyl oxidase in the context of collagen?
Catalyzing crosslinking reactions
What is the primary function of glycosaminoglycans (GAGs) in the extracellular matrix?
Maintaining hydration and deformability
What is the main function of the extracellular matrix?
Providing structure and support
What is the primary role of matrix metalloproteinases (MMPs) in the extracellular matrix?
Degrading extracellular matrix components
What are the effects of defects in the production of ECM proteins?
Specific or general problems
What is the significance of hydration in the extracellular matrix?
It is important for density and deformability
What is the primary function of glycosaminoglycans (GAGs) in the extracellular matrix?
Maintaining hydration and structural integrity
What is the primary role of collagen IV in the extracellular matrix?
Forming a mesh in basement membranes
What is the role of proteoglycans in the extracellular matrix?
Regulating hydration and ion balance
What is the source of sulfate added to glycosaminoglycans (GAGs) in the extracellular matrix?
Sulfotransferases
What is the primary function of basal lamina in the extracellular matrix?
Providing a barrier to microorganisms and large molecules
What is the primary function of glycosaminoglycans (GAGs) in the extracellular matrix?
Acting as side chains on proteoglycans
What is the role of hyaluronic acid in the extracellular matrix?
Existing separately and being a major component of the ECM
What is the primary role of collagen IV in the extracellular matrix?
Providing structural support
What is the significance of hydration in the extracellular matrix?
Binding positive ions and hydrogen bonds to water
What is the primary function of fibronectin in the extracellular matrix?
Connecting cells to the matrix
What is the primary function of proteoglycans in the extracellular matrix?
Linking to serine or threonine and forming a matrix with a high percentage of carbohydrates by weight
How does matrix degradation primarily occur in the extracellular matrix?
Through endocytosis and lysosomal hydrolases
What is the primary role of matrix metalloproteinases (MMPs) in the extracellular matrix?
Preventing excessive matrix remodeling
What is the primary function of basal lamina in the extracellular matrix?
Providing structural support
What is the primary function of lysyl oxidase in the context of collagen?
Forming cross-links in collagen fibrils
What is the primary role of elastin in the extracellular matrix?
Exhibiting elastic properties
What is the primary function of laminin in the extracellular matrix?
Connecting cells to the matrix
Study Notes
Extracellular Matrix and Connective Tissue Summary
- Glycosaminoglycans (GAGs) are composed of repeating disaccharide units, with one acid form and one with nitrogen and acetyl and/or sulfate.
- Sulfate is added from PAPS, and iduronic acid is made from glucuronic acid by an epimerase.
- GAGs are generally side chains on proteoglycans, and hyaluronic acid can exist separately.
- Proteoglycans are linked to serine or threonine, with a linker of xylose and galactose to start the repeat unit added to the linker.
- Matrix degradation occurs through endocytosis and lysosomal hydrolases, with chemical degradation possible due to glycation, reactive oxygen species, or other chemicals or enzymes.
- Defects in integrins, transmembrane proteins that connect to the matrix and cytoskeleton, can lead to diseases such as mucopolysaccharidoses (MPS).
- Matrix metalloproteinases (MMPs) containing zinc are important for migration and remodeling, and their activity is regulated by tissue inhibitors of metalloproteinases (TIMPs).
- The extracellular matrix (ECM) has various components, including collagen fibrils, elastin, and laminin, each with specific functions and properties.
- GAGs are important in the function of the ECM, and their failure in degradation can lead to MPS.
- Fibronectin attaches matrix proteins to integrins on cells, and integrins link the cytoskeleton to the matrix.
- The movement of tumor cells requires the activity of matrix metalloproteinases, and fibronectin has a major function in coordinating collagen deposition within the extracellular matrix.
- Assessment questions cover topics such as scurvy, cartilage cushioning, elastin properties, tumor cell movement, and fibronectin functions in malignant fibroblast cells.
Extracellular Matrix (ECM) Components and Functions Summary
- Glycosaminoglycans (GAGs) are composed of repeating disaccharide units, with sulfate added from PAPS and iduronic acid made from glucuronic acid by an epimerase.
- GAGs are side chains on proteoglycans, with hyaluronic acid existing separately and being a major component of the ECM.
- Proteoglycans are linked to serine or threonine, with many glycosyl chains added to the protein core, forming a matrix with a high percentage of carbohydrates by weight.
- The ECM serves as a filter, with negative charges binding positive ions and hydrogen bonds to water, creating a hydrated gel that limits the movement of larger molecules and cells.
- Proteoglycans bind to fibronectin, which in turn binds to integrins in cell membranes and collagen fibrils, thereby connecting cells to the matrix.
- In cartilage, the high number of negative charges attracts cations, creating high osmotic pressure and a network under tension, which can be compressed and regain shape after pressure is released.
- ECM components are both synthesized and degraded, with intercellular matrix being more organized and having a longer half-life for molecules compared to the near-cell matrix.
- Matrix degradation occurs through endocytosis, with lysosomal hydrolases breaking down components into sugars and amino acids, and chemical degradation can be caused by glycation, reactive oxygen species, or other chemicals.
- Defects in integrins, transmembrane proteins linking the matrix to the cytoskeleton, can lead to diseases, and matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) are important in the remodeling of the matrix and preventing excessive remodeling.
- The ECM comprises collagen fibrils, elastin, and laminin, each with its own unique role in the matrix, with GAGs being crucial in the function of proteoglycans.
- Assessment questions cover topics such as the synthesis of defective collagen molecules in scurvy, alterations affecting cartilage cushioning, the mechanism allowing elastin to exhibit elastic properties, proteins involved in tumor cell movement, and the major function of fibronectin.
- Understanding the ECM's components and functions is crucial for comprehending the structural and functional properties of various tissues and organs in the human body.
Test your knowledge of the extracellular matrix (ECM) with this quiz. Explore the functions and structure of major ECM proteins such as collagens, elastin, and laminin. Learn about the production of collagen and the effects of defects in ECM protein production, including scurvy, OI, and JEB. Delve into the world of glycosaminoglycans and more.
Make Your Own Quizzes and Flashcards
Convert your notes into interactive study material.
Get started for free
