Cell Structure Flashcards
What special structure is present in the stratum granulosum that binds keratin filaments together?
Keratohyaline granules (they are filled with histidine and cysteine rich proteins which bind the keratin filaments together)
What level of the epidermis are keratohyaline granules found?
Stratum granulosum
What substances do keratohyaline granules (present in stratum granulosum) contain?
Profilaggrin, loricrin, and involucrin
Where is fillagrin located?
Stratum Granulosum
What does filaggrin do?
Binds Keratin (like K 6/16) intermediate filaments and organizes into fibrils (like the glue that binds the keratins)
Where is filaggrin located?
In the keratohyaline granule in the stratum granulosum
Keratins found in the stratum granulosum
K2 and K10 (K11)
What enzyme crosslinks peptide bonds in the cornified envelope to make it into the insoluble compound y-glutamic lysine isopeptide bonds
Transglutaminase
What is the major protein component of the cornified envelope?
Loricrin
What enzyme crosslinks all the protein peptide bonds loricrin and involucrin to make the cornified envelope?
Transglutaminase 3
What are the two major proteins that make up the cornified envelope?
Involucrin and loricrin (fillagrin is the glue)
Which cornified envelope protein is the substrate for transglutaminase
Involucrin (this is the one that is upregulated in psoriasis)
What two cell proteins are upregulated in psoriasis, and which is downregulated?
Involucrin and K6/16 is upregulated
Loricrin is downregulated
(P5 in Jain)
Substrate for transglutaminase in the cornified envelope
Involucrine
Upregulated in all layers in Psoriasis except basal
Involucrin
Components of the basal layer (as a part of the DEJ)
Keratins K5/K14
K5/K14
Basal layer keratinocytes, part of the BMZ complex/DEJ
Hemidesmosome anchoring filament proteins
BPAG 1 BPAG 2 (Collagen XVII) Plectin Alpha-6, beta-4 integrin Tetraspan CD151 Laminin 332 (Laminin 5)
Collagen XVII
Same thing as BPAG II
What collagen is found in the lamida Lucida/basal layer
Collagen XVII - same thing as BPAG II
Plectin
A Heim-desmosome anchoring filament protein - found in the basal layer/lamida lucida along with BPAG I,II, integrin, and laminin 5 (332)
What type of collagen is found in the lamida densa?
Collagen IV
Type IV collagen found where?
Lamina Densa
Major components of lamina densa?
Type IV Collagen Heparin Sulfate proteoglycans Laminin 311 (6) Laminin 511 (10) Nitrogen (Also tecnically some of laminin 5(332)
Major components of the sublamina densa
Type VII collagen Type III collagen Type I collagen Elastin Fibrillin Latent TGB-beta proteins
Where is type VII collagen found?
Sublamina densa
Major protein comprising Anchoring Fibrils?
Type VII Collagen
What are anchoring fibrils made of and where are they found?
Made of Type VII collagen and they are found in the sublamina densa
What protein connects the lamida lucida to the lamina densa?
Laminin 332 (Laminin 5)
Members of the plakin family
Plectin BPAG 1 BPAG 2 Envoplakin Desmoplakin Periplakin
Major function of plectin
Attaches keratin filaments in the basal layer to the anchoring filaments in the hemidesmisome
Mutation in plectin causes what disease
EB with muscular dystrophy
How many kD is BPAG1?
230kD
Which is intracellular and which is a transmembrane protein:
BPAG 1
BPAG 2
BPAG 1 - intracellular
BPAG 2 -transmembrane
How many kD is BPAGII?
180kD
How many kD is the EXTRACELLULAR portion of BPAGII?
120kD
Name 4 diseases that target BPAG2?
Bullous Pemphigoid
Pemphigoid Gestationis
Linear IgA Bullous Dermatosis
Cicatricial Pemphigoid
Which part of the BPAG2 protein does BP, Pemphigoid Gestationis, and Linear IgA target?
NC16 terminus (which is the most superficial extracellular portion of the BPAGII protein)
Vs cicatricial pemphigoid which targets the distal carboxy-terminus which inserts through the lamina lucida into the lamina densa
Which disease targets the carboxy terminus of BPAGII?
Cicatricial pemphigoid
What genetic disease has a defect in BPAG2 (BP180)
Non-Herlitz Junctional EB (widespread bulla at birth, heals with atrophic scarring, alopecia, improves with time)
Aquired disease, and genetic disease caused by mutation in integrin subunit beta-4
Aquired disease - cicatricial pemphigoid with ocular involvement
Congenital - Junctional EB with pyloric atresia
Genetic & Aquired disease caused by mutation in Laminin-5 (332)
Genetic - Junctional EB, Herlitz type
Aquired - anti-epiligrin cicatricial pemphigoid
Type VII Collagen genetic and aquired disorders
Genetic: ALL Dystrophic EBs
Aquired: EB Aquisita, Bullous lupus
What is the only type of protein that is present in both adherents junctions AND desmosomes?
Plakoglobin (mutated in Naxos)
What cell transmembrane protein do Langerhans Cells use to connect with keratinocytes
E Cadherins
Name the armadillo proteins
B-Catenin
Plakoglobin
Plakophilin
Name the caderhins
Desmogleins Desmocollin E caderhin P cadeherin N caderhins
Which are quick but weak cellular adhesions
Adherens junctions
Which are slow but strong intracellular junctions
Desmosomes