ECM Flashcards
Network Forming Collagens (2)
Types 4, 7
Collagen type 12: type, location, disease
Fibril-Associated with type 1, found in tendons and ligaments, no disease
3 GAGs in ECM and their properties
- Hyaluronic Acid—no sulfate, no attached protein
- Heparan Sulfate- sulfate attached, protein attached (Membrane bound associated with Syndecan; Extracellular associated with Perlecan)
- Chondritin Sulfate-sulfate attached, protein attached
Laminin
Adhesion Glycoprotein that is the major component of the basal lamina (associated with Integrins a6B1, a7B1, and a6B4)
Fibronectin
Adhesion glycoprotein with modular organization (domains with distinct functions)
RGD sequence binds other ECM proteins
Associated with Integrin a5B1
Biosynthesis of collagen: which collagens, where does it begin, where does it end, what are the key steps, what cofactor do you need
Involves Collagens 1,2,3,5,11 (fibril forming)
Beings in ER (cotranslational transported there)
Ends in ECM
1. Pro-a chains hydroxylated then glycosylated
2. Assemble with extension peptides
3. 3 chains form triple helix
4. Secreted from cell via sec. Vesicle
5. Extension peptides cleaved
6. Self assembly into fibril
7. Fibril–>collagen fibers
*need Vit C
Type 17 Collagen: type, location, disease
Transmembrane collagen, located with hemidesmisomes
Disease=Bullous Pemphigoid
Transmembrane Collagens (1)
Type 17 Collagen
Collagen type 11: type, location, disease
Fibril forming, associated with type 2, regulates diameter, no disease
B2 Integrin mutation
Issue with WBCs stopping (Leukocyte Adhesion Deficiency)
Fibril Forming Collagen Types (5)
1, 2, 3, 5, 11
Type 4 Collagen: type, location, disease
Network forming Collagen (forms chicken wire sheets), located in basal lamina
No disease
*Does not cleave extension peptides
Collagen type 5: type, location, disease
Fibril forming associated with type 1, regulates diameter (no dx)
Integrin—–Ligand—Where
6 total
a5B1---Fibronectin---all over a6B1---Laminin---all over a7B1---Laminin---muscle aLB2---IgSuperfamily---WBC a2B3---Fibrinogen---platelets a6B4---Laminin---Hemidesmisomes (epithelia)
Elastin-where assembled, key structural aspects (2), function
Assembled in ECM
Highly cross linked, and made of fibrillin surrounded by microfibrils
Resilience
Type 7 Collagen: type, location, disease
Network forming collagen/Anchors fibrils, located between the stratified squamous epithelia
*has disulfide bonds
Disease=Epidermylosis Bullosa (anchoring fibrils disrupted, epithelium and basement membrane pulled apart)
3 Main PGs in ECM, main features of each
- Aggrecan–GAG chain=chondritin sulfate, keratin sulfate; found in cartilage, strength
- Syndecan–GAG chain=heparan sulfate, chondritin sulfate; found in fibroblasts and epithelial cell surface; binds to FGF ligand (GFs), adhesion
- Perlecan—GAG chain= heparan sulfate, found in basal lamina, structural and filtering function
Collagen type 3: type, location, disease
Fibril-Forming (specifically this forms reticular fibers–special silver stain), located in skin, blood vessels, organs
Disease associated=Ehlers Danlos Syndome/anneurism, hyperextendible skin
Collagen Type 9: Type, Location ,Disease
Fibril-Associated, associated with type 2 (cartilage)
Disease=Epiphyseal Dysplasia, joint issues/arthritis
*does not cleave extension peptides
Fibril Associated Collagens (2)
Types 9, 12
PGs in ECM-function and structure
Function- present GFs to membrane receptors
Structure: Core protein with GAG side chains bound covalently
Basement membrane (3 zones in order top to bottom)
TOP 1. Lamina Rara
- Lamina Densa
- Lamina Reticularis BOTTOM
GAGs in ECM: features (5)
“Glycosaminoglycans”
- neg charge
- osmotically active
- can bind H20
- compressible
- highly extended
Elastin diseases (2)
- Marfarns Syndrome: Mutation in Fibrillin 1–aortic rupture, MV prolapse, very long limbs, lack of recoil
- Elastoderma: reduced recoil
