EB

Question 1

describe an IF’s structure? how many polypeptides in total is an If? what parts are variable? what parts are conserved?

Answer 1

-highly conserved central rod thats has 4 helicl and 3 nonhelical (L1 2 3) regeions -variable ends -coiled coils of this rod to make a dimer w hydrophobic greasy seam -become antiparaellel tetramer protofilament (4), 2 tetramer=protofibril -4 protofibrils make an IF=32 polypeps all together

Question 2

What are relative lengths of actin, IF, and microtubules?

Answer 2

actin 5 nm IF 10 nm microtubules 25 nm

Question 3

how do the dimers pack laterally? what part of the dimer is responsible for binding to the ends of another dimer?

Answer 3

L1-2 region, mutations here cause keratin clumping and weak/thin filaments

Question 4

Where does EBS present? what are the dominant and recesive forms?

Answer 4

-above basal lamina (in epidermis) -dominant: abnormal protein formed -recessive: not enough protein formed

Question 5

Where do EBS mutations occur commonly….what are the characteristics of the heterodimer that is effected…

Answer 5

k5(basic) /k14 (acidic) obligate hetrodimers

Question 6

What are the 3 subtypes of EBS and how do they vary in severity..how does the location of the mutation effect the severity?

Answer 6

Downling meara is worst>weber cockayne>koebner…DM worst bc its a mutation near the ends

Question 7

which keratins are bigger/more basic and which are smaller and more acidid?

Answer 7

1-8 basic 10-19 acidic

Question 8

wheres JEB? how inherited?

Answer 8

within basal lamina (junction bw epidermis and dermi….a hemidesmosomal adhesion to lamina disease autosomal recessive

Question 9

Forms of JEB? name the proteins

Answer 9

Plectin – JEB + muscular dystrophy BPAG2- GABEB integrin a6b4 Laminin 5- anchoring filament, Herlitz

Question 10

DEB? what are they predisposed for? AD or AR?

Answer 10

dystrophic. most severe. lack of collagen VII (anchoring fibril)…supposed to sew dermis to epidermis -skin cancer

Can be either AD or AR

Question 11

What is Collagen VII’s structure and how is it important?

Answer 11

triple helix with non collagenous heads…tails line up to form disulfide bond?? bivalency important for stitch??

Question 12

what is EH? which Keratins are effected here?…what’s another type of EH

Answer 12

Epidermolytic Hyperkeratosis. K1 K10…suprabasal, skin can try to respond by hyperproliferating=elephant systemized epidermal nevus=mosaic form

Question 13

K5 K14 is in what cells?

Answer 13

basal cells of all stratified epithelia, more widespread than other keratin problems

Question 14

What other tests besides pedigree/physical must one do to determine type of EB

Answer 14

immunofluoresence if blister on floor know its epidermal EBS, on roof know its dermal issue DEB

Question 15

What are three autoimmune hemi-desmosomal diseases?

Answer 15

Bullous pemphigoid BPAG1 rare Cictricial Pemphigoid autoantibodies against laminin V EB Aquisita-Collagen VII

Question 16

What are the different genetic and autoimmune diseases that effect each layer

why is basal layer so tall?

what are spinous?

Answer 16

stratus cornum

granular

spinous cells dont touch basal lamina…they’re the terminal differentiation

basal layer: big nucleus bc proliferating

basal lamina

dermis

Question 17

what are the different proteins that comprise a hemidesmosome?

Answer 17

IF=keratin anchoring to plaque proteins (plectin)
Plectin attach to integrins (transmembrane)

BPAG-2 collagenous like adhesion molecule that attah to ECM proteins like laminen

Anchoring filaments made of laminen
Anchoring fibrils are collagen 7