Flashcards in Epithelium II Deck (27):
What is the general blueprint for junctional complexes?
1) Cytoskeletal elements2) Intracellular anchor proteins3) Cell adhesion molecules
What is the role of claudins?
Required for tight junction formation and function
What molecules are required for tight junction formation and function?
Loss of claudin 9 leads to what condition?
Loss of claudin 5 leads to what condition?
Breach of blood-brain barrier
What does Helicobacter pylori disrupt?
What are the ZO (zonula occludens) proteins?
Peripheral proteins located on the cytoplasmic side of the plasmalemma that anchor claudins and occludins to actin cytoskeleton
What is the function of ZO proteins?
Anchor claudins and occludins to the actin cytoskeleton
What are the functions of the zonula occludens (tight junctions)?
1) Selective movement2) Prevent cell separation3) Regulate epithelial proliferation4) Establishing functional polarity
What is contained in the zonula adherens (intermediate junctions)?
1) Intracellular anchor proteins (a- and B- catenins, actinin, vinculin) which attach to actin microfilaments2) Transmembrane adhesion proteins or CAMs (e.g. e-cadherin)3) Actin microfilaments of zonula adherens form terminal web
What is contained in the macula adherens (desmosome)?
1) Intracellular anchor proteins - intermediate filaments attach at these sites2) Transmembrane adhesion proteins (e.g. cadherins like desmoglein, desmocollin)
In pemphigus vulgaris, patients develop antibodies against what protein?
Desmoglein 3 of desmosomes
What are the symptoms of pemphigus vulgaris?
Blistering of the skin
What is contained in focal adhesions?
1) Intracellular anchor proteins - actin filaments attach to these sites2) Transmembrane adhesion proteins (integrins) anchor cell to proteins of ECM
What is the function of focal adhesions?
Anchors cell to proteins of ECM
What is the function of the hemidesmosome?
Anchors basal plasma membrane to underlying basal lamina
What is contained in the hemidesmosome?
1) Intracellular anchor proteins - intermediate filaments attach at these sites2) Transmembrane adhesion proteins (integrin and collagen) interact with ECM of basal lamina
In Bullous pemphigoid, autoantibodies develop against what protein?
Type XVII collagen
What is a nexus?
What is a connexon?
Hollow cylindrical structure formed by six transmembrane proteins called connexins
What types of connections are present in a nexus?
Electrical and chemical
Where are nexuses (gap junctions) especially numerous?
1) Cardiac muscle2) Smooth muscle3) Hepatocytes
What is an in situ carcinoma?
A cancer type that has not penetrated through the basal lamina
What is the term for a cancer that has not penetrated the basal lamina?
In situ carcinoma
What is an invasive carcinoma?
A cancer type that has penetrated through the basal lamina
What is the term for a cancer that has penetrated the basal lamina?