Cell Junctions Flashcards
What does the adherens junction connect
actin filament bundles between cells
Name two examples of adherens junctions
epithelial, neural cadherins
What are adherens junctions dependant on
calcium
what are cadherins
type 1 transmembrane proteins
What is integrin dependent on
calcium and magnesium
What do adherens junctions link to
actin cytoskeleton
What are the similarities between focal adhesion and adherens junctions
linked to actin cytoskeleton, transmembrane proteins
What do the transmembrane proteins bind to in adherens junction and focal adhesion
extracellular ligand
What is present in both focal adhesion and adherens junctions
vinculin
What is vinculin
conserved cytoskeletal protein
What proteins are predominant in focal adhesion
talin and filamin
What is the process of the adhesion belt - morphogenesis
cadherin to catenin to actin to myosin
What drives contraction of the adhesion belt
different cadherins
What is the function of E-cadherin in the adhesion belt
links rest of cell layer
Where is N-cadherin located?
top edge of cell
What do desmosomes form
cell-cell junctions linked to intermediate filaments
Where are desmosomes found
heart muscle, epidermis
What do hemidesmosomes attach to
cells to basal lamina
What do hemidesmosomes involve
integrins and intermediate filaments
What is pemphigus
autoimmune disease
What are the symptoms of pemphigus
skin blistering
Where are tight junctions located
top of the cell
What do tight junctions form
barrier between lumen of vessel
What are the roles of tight junctions
barrier in gut epithelia, paracellular transport
Describe the tight junction
semi permeable
What do zonula occluden proteins bind to
claudin, occludin, and actin
What can tight junctions help form
membrane compartments
What do tight junctions allow
segregation
What is on the apical membrane of membrane compartments
glycolipids, cholesterol
What do membrane compartments allow to be maintained
polarity
What is on the basolateral membrane compartment
phoshatidylcholine
Where are gap junctions present
connective tissue, epithelia, neurons, heart muscle
Describe gap junctions
range of sizes, close proximity, wide distribution
What forms 1 connexon
6 connexins
How is membrane potential regulated
pH, Ca2+ and cell signals
What are selectins
molecules on cell surface that bind to sugars
What is the effect of damage to selectins
effects properties of endothelial cells
What is the function of selectins
attach to sugar molecules on leukocytes
What is the effect of selectins binding to leukocytes
forms strong junctions - help with damage
What are cadherins dependent on
calcium ions
