Lecture 8 Flashcards
What are the types of cell-cell anchoring junctions
Adherens junctions, desmosomes
What are the types of cell to ECM junctions
Focal adhesions, hemidesmosomes
What are the types of trafficking junctions
Tight junctions, gap junctions
What are the types of structural proteins
Collagen, elastin
What are the types of adhesive proteins
Fibronectin, laminin
Adherens junctions function, transmembrane protein component, filament component
Function: link adjacent cells
Transmembrane protein component: Classical cadherins
Filament component: Actin cytoskeleton (actin-belt)
Desmosomes function, transmembrane protein component, filament component
Function: Intercellular adhesion
Transmembrane protein component: Desmosomal cadherins (desmoglein and desmocollin)
Filament component: Intermediate filaments
Desmosomes and their strong interactions with __________ allows the tissues to withstand _________ forces
Intermediate filaments, tearing/shearing
Membrane function/ protein components of focal adhesions
Function: Attaches migrating cells to the extracellular matrix
Protein components: integrin dimers link the actin cytoskeleton to proteins within the ECM
(fibronectin or collagen)
Filament components: Actin filaments
Filament component/ function/ protein components of hemidesmosomes
Filament component: Intermediate filaments (cytosolic side); laminin (ECM side)
Function: Anchor epithelial cells to the basal lamina
Protein components: Integrins
Tight junctions function, transmembrane protein component
Function: Form a tight seal that inhibits paracellular transport/prevent mixing of apical and basolateral membrane proteins
Transmembrane component: Claudins, Occludin
Fibrillar collagen provides
Mechanical strength
Collagen can be found where
Type IV collagen is a major component of basal lamina.
Hydrophobic/ hydrophilic elastin is involved in what
Hydrophobic domains play an important role in elasticity. Lys in hydrophilic domains are involved in cross-linking of elastin
A proteoglycan is composed of
Glycosaminoglycans which are covalently bound to a core protein
GAGs are composed of
Unbranched chain of repeating disaccharides
GAGs contain what
Acidic/ sulfated sugars which make them a negative charge
Fibronectin does what
Links the molecules in ECM (collagen, proteoglycan), Plays a role in cell migration through ECM
Laminin functions
Another major component of basal lamina
Pemphigus cause/ function affected/ characteristic features
-Autoantibodies against the desmoglein
-Disruption of desmosomes (i.e., adjacent epithelial cells are loosely connected/separated easily)/Blisters, raw & crusted wounds
Osteogenesis imperfecta cause/ function affected/ characteristic features
-Inherited mutations in type I
collagen (~90% cases)
-Decreased production of collagen or
production of abnormal collagen/Fracture
after minimal trauma, bone deformation
Ehlers-Danlos syndrome cause/ function affected/ characteristic features
-Defective collagen synthesis
(due to inherited mutations in
collagen or collagen processing enzymes)
-Stretchy skin, hypermobile joints, easy
bruising (symptoms vary)
Scurvy cause/ function affected/ characteristic features
-Prolonged vitamin C deficiency
-Impaired hydroxylation of proline and lysine in
collagen (Prolyl hydroxylase and lysyl
hydroxylase require vitamin C for their
activity)
What is the proteoglycan core composed of
Core protein+ GAG’s+ PGs linked to hyaluronic acid via linker protein
What are the 8 steps of collagen synthesis
