Extracellular matrix Flashcards
What are the two types of components of the ECM?
Fibrillar and non-frbillar
What is the function of the ECM?
Architectural (Mechanical stability)
Instructional (Influences cell behaviour)
Physical support, mechanical and physicochemical properties of tissue: Influences growth, adhesion, differentiation, and status of cells
What molecules do connective tissue comprise of?
Proteoglycans
Collagen
Glycoproteins (Multi-adhesive)
Which Collagen molecules are fibrillar?
Type 1-3
Which collagen forms the basement membrane?
Type 4
Name 3 multi-adhesive glycoproteins?
Laminins, fibrogen, fibronectin
Name 4 proteoglycans?
Aggrecan, Versican, Decorin, Perlecan
Why can collagen form a tight-compact helical structure?
Glycine-x-y repeat has a single variable group consisting of a hydrogen ion, therefore spatially occupying minimal space
What is the secondary structure of collagen?
Involves hydrogen bonding which occur between the amino and carboxyl groups of the amino acid to form the left handed helix
What is the quaternary structure?
3 polypeptide helices (Homotrimer) bond together to form a right handed triple helix, helical structure structure is maintained through hydrogen bonding
Crosslinking bridges
How do collagen fibrils form?
Covalent bonding between multiple triple helices
What are the structural properties of collagen?
They provide high tensile strength and flexibility
Name the genetic disease attributed to dysfunctional triple helix collagen:
Osteogenesis imperfecta
Is collagen 1 a heterotrimer or homotrimer?
Heterotrimer
2- alpha 1
alpha 2(1)
What type of trimers are collagens 2 &3?
Homotrimers
alpha-1-2) and alpha (1-3
What contributes towards interchain hydrogen bonding within collagen molecules?
The hydroxylation of proline via post-translational modification (Holds the triple helix)
Hydroxyproline
What is the purpose of lysine and hydroxylysine?
Formation of covalent cross-linkages between collagen molecules
What is the pathophysiology of scurvy?
Vitamin C deficiency
Vitamin C is a cofactor for the hydroxylation of proline and lysine (Prolyl hydroxylase and lysyl hydroxylase)
Underhydroxyalted collagens result in a reduction of tissue stability
Where are collagen pro-alpha chains formed?
Ribosomes
What is Ehlers-Danlos Syndrome (EDS)?
Inherited connective tissue disorder
Symptoms: Stretchy skin, and loose joints
Mutations in collagen, reducing collagen structure, and processing
What two fibres do basement membranes comprise of?
Mucopolysaccharides and protein fibres