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BMS242 - Cell and Molecular > Cell Adhesion Molecules > Flashcards

Flashcards in Cell Adhesion Molecules Deck (15)
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What is the importance of cell adhesion?

Sperm adhere to the eggs to transfer material
Brings cells within the egg together to form to morula (E-cadherin)
Inner cell mass and trophoblasts of embryos expressed different adhesion properties
Implantation of egg into endometrium wall
Over time more cell types develop which form due to differential adhesion
Neural crest cells becoming nerve cells involves adhesion


What makes L-cells useful for studying cadherins?

They don't express any cadherins so they can be transfected and studied


What is the outcome of transfecting L-cells with E-cadherin and N-cadherin?

Homophillic sorting


What is the outcome of transfecting L-cells with E-cadherin but at different levels of expression?

Graded sorting


Describe cadherin linkage

Calcium binds to the hinge regions to stabilise them which allows them to interact with neighbouring cells


How do rows of cadherins interact?

Perpendicular (these perpendicular arrays act like velcro and allow adhesion)


What are the roles of hypervariable protocadherins?

Specifying synapses within the brain, neurite self avoidance


What are a couple of intracellular proteins that are important in cadherin function?

Catenins, bind to intracellular region of cadherin to link cadherin to cytoskeleton
Beta-catenin can regulate proliferation via c-Myc
They can sense when cells are interacting with neighbouring cells
When cadherin interacts with a neighbouring cell you get tension that stretches out the cell membrane that causes a conformational change of catenin to a folded to an open state, vinculin can bind


How can Rho be activated?

B-catenin activated junction formation, strong actin filaments form


What does mutant Rho lead to?

Constitutive activation of Rho leading to stress fibre formation


How does cadherin expression change in the early nervous system?

Only E-cadherin expressed in the early embryo
Newly formed mesoderm cells lose E-cadherin
N-cadherin replaces E-cadherin in the neural tube
Cadherin 7 - neural crest cell identity


What are the features of selectins?

Cell surface, Ca2+ dependent, bind carbohydrates on neighbouring cells


What are the roles of selectins?

Neutrophil trapping


What are the roles of Ca2+ independent CAMs?

Mediate homophillic binding, mediate interactions with ECM and between neighbouring cells


How do Ca2+ independent CAMs arise?

Alternative splicing