L21 - Cell Adhesion Flashcards
Describe what may happen if a cell fails to migrate and aggregate
Leads to cell, tissue, organsims dysfunction and possibly death
Describe the migration of the neural crest ceells
Migrate from the dorsal neural tube
Aggregate in the somites (around)
Form the peripheral ganglia
Sponges are able to
Reagregate
Sponges reagregating is limited to
Their own species
What are embryonic tissues able to sort by
Tissue type
In aggregation you often see
Regionalisation
In a cell line of cells expressing N cadherin and others expressing E cadherin what happens
Homophilic sorting (same CAM together)
In a cell line with some cells expressing high E cadherin and others expressiong low E cadherin, what occurs
Homophilic sorting (so high expressing in the center - low expressing around the outside
Cadherins are
integral membrane glycoproteins
What binds to cadherins what does this cause
Ca can bind -
Conformational change due to binding
What are the different types of classical cadherins
E, N, P, VE - cadherin
What is the main location of E-cadherin
Many epithelila
What do hypervaribale protocadherins have roles in
Specification of the synapses
Neutrite self avoidance
Catenins link to
Actin
What can B-catenin regulate
Cell proliferation via c-myc
Describe the processes involved in the formation of cell junctions
Myosin/actin interaction
Expsoes vinculin binding site
Cross linking in more actin filaments
What is one of the main things effected in rho mutants
The cytoskeleton
Describe what is seen when Rho is consituively active
Leads to the formation of stress fibres
What is Rho
Family of GTPase part of the larger Ras family
What CAM is expressed in the early embryo
E-cadherin
The newly formed mesodermal cells lose expression of
E-cadherin
What is expressed in the neural tube replacing E-cadherin
N-cadherin
Which cells express cadherin 6B
Floor plate and roof plate
Which cells express cadherin 7
Neural crest cells
Where are selectins located
Cell surface
What do selectins bind
Ca
What are selectins dependent on
Ca
What do selectins bind
Carbohydraes
Give an example of a process requiring selectins
Neutrophil trapping
What is the major form of Ca independent cell adhesion molecules
Neural cell adhesion molecules (N-CAMS)
How do Ca independent CAMs bind
Homophilically
What do Ca independent CAMs bind
ECM and Cell binding
How many genes for Ca independent CAM
If this is the case then how are there so many Ca independent CAMs
Single gene
Alternative splicing and post translational modification
What is the major post transltional modification of Ca independent CAMS
Glycosylation
Polysialic acid in Ca independent CAMs
More means what
Where is more often seen
More present in immature forms
More polysialic acid means there is LESS adhesion
