L21 - Cell Adhesion

Question 1

Describe what may happen if a cell fails to migrate and aggregate

Answer 1

Leads to cell, tissue, organsims dysfunction and possibly death

Question 2

Describe the migration of the neural crest ceells

Answer 2

Migrate from the dorsal neural tube
Aggregate in the somites (around)
Form the peripheral ganglia

Question 3

Sponges are able to

Answer 3

Reagregate

Question 4

Sponges reagregating is limited to

Answer 4

Their own species

Question 5

What are embryonic tissues able to sort by

Answer 5

Tissue type

Question 6

In aggregation you often see

Answer 6

Regionalisation

Question 7

In a cell line of cells expressing N cadherin and others expressing E cadherin what happens

Answer 7

Homophilic sorting (same CAM together)

Question 8

In a cell line with some cells expressing high E cadherin and others expressiong low E cadherin, what occurs

Answer 8

Homophilic sorting (so high expressing in the center - low expressing around the outside

Question 9

Cadherins are

Answer 9

integral membrane glycoproteins

Question 10

What binds to cadherins what does this cause

Answer 10

Ca can bind -

Conformational change due to binding

Question 11

What are the different types of classical cadherins

Answer 11

E, N, P, VE - cadherin

Question 12

What is the main location of E-cadherin

Answer 12

Many epithelila

Question 13

What do hypervaribale protocadherins have roles in

Answer 13

Specification of the synapses

Neutrite self avoidance

Question 14

Catenins link to

Answer 14

Actin

Question 15

What can B-catenin regulate

Answer 15

Cell proliferation via c-myc

Question 16

Describe the processes involved in the formation of cell junctions

Answer 16

Myosin/actin interaction
Expsoes vinculin binding site
Cross linking in more actin filaments

Question 17

What is one of the main things effected in rho mutants

Answer 17

The cytoskeleton

Question 18

Describe what is seen when Rho is consituively active

Answer 18

Leads to the formation of stress fibres

Question 19

What is Rho

Answer 19

Family of GTPase part of the larger Ras family

Question 20

What CAM is expressed in the early embryo

Answer 20

E-cadherin

Question 21

The newly formed mesodermal cells lose expression of

Answer 21

E-cadherin

Question 22

What is expressed in the neural tube replacing E-cadherin

Answer 22

N-cadherin

Question 23

Which cells express cadherin 6B

Answer 23

Floor plate and roof plate

Question 24

Which cells express cadherin 7

Answer 24

Neural crest cells

Question 25

Where are selectins located

Answer 25

Cell surface

Question 26

What do selectins bind

Answer 26

Ca

Question 27

What are selectins dependent on

Answer 27

Ca

Question 28

What do selectins bind

Answer 28

Carbohydraes

Question 29

Give an example of a process requiring selectins

Answer 29

Neutrophil trapping

Question 30

What is the major form of Ca independent cell adhesion molecules

Answer 30

Neural cell adhesion molecules (N-CAMS)

Question 31

How do Ca independent CAMs bind

Answer 31

Homophilically

Question 32

What do Ca independent CAMs bind

Answer 32

ECM and Cell binding

Question 33

How many genes for Ca independent CAM

If this is the case then how are there so many Ca independent CAMs

Answer 33

Single gene

Alternative splicing and post translational modification

Question 34

What is the major post transltional modification of Ca independent CAMS

Answer 34

Glycosylation

Question 35

Polysialic acid in Ca independent CAMs

More means what

Where is more often seen

Answer 35

More present in immature forms

More polysialic acid means there is LESS adhesion