Extracellular matrix (deevska) Flashcards
4 major components of Extracellular matrix?
Collagen fibers- gives tissue tensile strength
Elastic fibers- elasticity to tissue
Proteoglycans and hyaluronic acid- gel like or slimy
Glycoproteins- glue holds fibers and cells together
ECM components are very abundant in the eye. What are some parts of the eye that are involved?
Sclera, Cornea, Lens, vitreous humor, Bruch membrane
What is the most abundant protein in the human body? Long, rigid structure in which 3 polypeptides are wound around one another in a rope like triple helix.
Collagen fibers
Collagen fibers structure is rich in 2 amino acids, what are they?
Proline
Glycine (about every 3 amino acids)
Hydroxylysine may be ___________ with glucose or galactose before the formation of the triple helix.
glycosylated
__________ is required as a cofactor for the enzymes involved in hydroxylation of proline and lysine residues in collagen. Lack of this leads to what disease?
Vitamin C
Scurvy
Lack of proline and lysine greatly decrease the tensile strength of the assembled fiber, how?
interchain H-bond formation is impaired which prevents formation of stable triple helix
Cross linking occurs extracellularly by what enzyme?
Lysyl oxidase (cu containing enzyme)
What disease is copper deficiency?
X-linked Menkes disease
What disease is Copper overload?
wilson disease
What is a defect in any synthetic steps?
Collagenopathies
What disease leads to brittle hair (kinky hair disease) because of lack of copper?
Menkes syndrome (MNK)
What disease is from too much copper in the body and has kayser-Fleischer rings in the eye?
Wilson’s disease
What disease has brittle bones and two types where (Type 1 is less severe and Type 2 is fatal in utero or in neonatal disease)? Blue sclera and hearing loss also involved
Osteogenesis Imperfecta (OI)
Ehlers-Danlos Syndrome has what characteristics?
defective collagen genes Leads to: elastic skin hypermobile joints easy bleeding
Elastic fibers have a composition of what?
Inner core of amorphous elastin
She said this could be a question on test… But I didn’t hear the question… just the answer… on slide 12
Has very little post transcriptional modifications (hydroxyproline and hydroxylysine)
INsoluble protein polymer synthesized from a precursor _________.
Tropoelastin
Extensively interconnected, rubbery network that can stretch and bend in any direction when stressed, giving _____________ elasticity.
connective tissue
What is the cause of Marfan’s syndrome?
mutations in the fibrillin-1 protein
rare dominantly inherited condition
pts are unusually tall with long spidery gingers and the lens is displaced
What are large complexes of heteropolysaccharide chains associated with a small amount of protein.
Proteoglycans
What are proteins with a variable but typically small amount of carbohydrate (2 to 10 sugar residues)
Glycoproteins
Proteoglycans functions:
Produce a gel-like matrix
Form the basis of the body’s ground substance
Flexible support
etc…
Large complexes of negatively charged heteropolysaccharide chains.
Unbranched
repeating dissaccharide units
Glycosaminoglycans
GAGs have a strong (-) charge due to ______ groups and ______ groups.
carboxyl
sulfate
What are the 6 classes of GAGs?
Chondroitin 4 and 6 sulfates
Keratan sulfates I and II- (I found in corneas)
Hyaluronic acid- animal and bacteria tissues
Dermatan sulfate- skin
Heparin- mast cells (anticoagulant)
Heparan sulfate- (same as heparin except acetylated) also extracellular GAG
Be able to locate a specific GAG to a location in the human body…
slide 21
Where is synthesis of core protein happening?
ER lumen –> Golgi where it is glycosylated by glycosyltransferases to form short carbohydrate linkage region
Active transport mechanism that requires energy, cells engulf stuff and end up in the _________.
Phagocytosis
Lysosomes
What is a disease that is the most severe form of MPS and leads to corneal clouding. What is the other disease that leads to corneal clouding, very rare?
Hurler syndrome
Sly syndrome
This disease is X-linked and has NO corneal clounding.
Hunter syndrome
What is a protein with a variable but typically a small amount of carbohydrate (2 to 10 sugar residues).
Glycoproteins
Membrane bound glycoproteins participate in cell surface recognition by what 3 ways?
cell to cell contact
hormones
viruses
IN the golgi, glycoproteins to be secreted from the cell are packaged into vesicles that fuse with the cell memabrane and release their content
Soluble glycoproteins
Glycoproteins destined to be components of the cell membrane are integrated into the ER membrane, pass through the Golgi, and are packaged into vesicles targeted for delivery to the cell membrane
Membrane glycoproteins
This occurs in the ER, additional sugars and modifications may be added in Golgi
N-linkage
This occurs only in the Golgi apparatus
O-linkage
_________ glycoproteins can be phosphorylated at specific mannose residues
N-linked
What disease is a deficiency in the ability to phosphorylate mannose…
Accumulation of large lysosomal inclusion bodies
I-cell disease
