091614 basement membrane Flashcards
structure of basement membrane zone
hemidesmosome
lamina lucida
lamina densa
sublamina densa
in pts with inherited blistering diseases, what is the basis?
genes encoding some structural proteins of the basement membrane zone are mutated
BP 230
bullous phemphigoid antigen 1
from the plakin family of proteins
cytoplasmic localization
important for cytoskeletal organization
BP 180
bullous pemphigoid antigen 2
also known as type XVII collagen
transmembrane protein that connects basal keratinocytes through BP 230 to the cytoskeleton and through laminin 332 to dermal collagen VII
bullous pemphigoid (BP)
tense blisters (fluid could be clear or hemorrhagic)
antibody binding to BP antigens causes subepidermal separation
BP is the most common
autoimmune bullous dermatosis
BP occurs primarily in whom
elderly
stages of BP
early: highly pruritic urticaria w/o blistering
later: tense blisters with serous or rarely hemorrhagic content (very stable blisters in contrast to pemphigus groups of diseases)
antibodies in BP are directed against what?
BP 230 and BP 180
generalized atrophic benign epidermolysis bullosa
mutated BP 180 protein
synonyms are collen type XVII and bullous pemphigoid antigen 2
clinical presentation of generalized atrophic benign epidermolysis bullosa
blisters
loss of hair
lamina lucida
immediately underlies hemidesmosomes
LL may be an artifact of tissue prep and dehydration
lamina densa
composed mostly of type IV collagen (one of the most abundant collagens of the BMZ) and laminins
key laminin is laminin 332 (prev known as laminin 5)
what makes up more than 1/2 of the mass of the BMZ
type IV collagen
what does laminin 332 do?
laminin 332 binds to hemidesmosomal protein integrin alpha6beta4 on the basal keratiocytes and to type VII collagen in the dermis, providing adhesion