Adhesion And Extracellular Matrix

Front 1

What is the difference between chadherins and integrins?

Back 1

cadherins - cell-cell binding homophilic
integrins - cell - matrix

Front 2

What are two actin based cell adhesion?
What are 2 intermediate filament based cell adhesion?

Back 2

adherens: cell-cell and focal adhesions: cell-matrix

Desmosomes, hemidesmosomes

Front 3

What is meant by structurally polarized cells?

Back 3

anchored to the tissue on the basal side and free of attachments on the apical side

Front 4

What filament do cadherins bind to and what ion are they dependent on?

Back 4

Actin
Ca2+

Front 5

How do cell-cell junctions bind? homophilic or hetero philic
cell-matrix?

Back 5

cell-cell - homophilic
cell-matrix are heterophilic

Front 6

In cadherins there are E, N, P, VE were are these found?

Back 6

E- epithelial
N - neurons
P - placenta
VE - vascular endothelial

Front 7

cadherins are important in tissue formation

Back 7

...neural tube

Front 8

What do selectins mediate?

Back 8

transient cell-cell adhesions via carbohydrate-binding proteins

Front 9

What protein makes up tight junctions?

Back 9

cluadins, occludins,

Front 10

What protein is a gap junction formed by? What are a group of 6 of these called, how many groups of 6 are required for a gap junction?

Back 10

Connexins
Connexon (hemichannel)
Many connexon pairs to give a fixed diameter of the lumen

Front 11

What is gap junction permeability regulated by?

Back 11

cells, cytosolic pH or free cytosolic Ca 2+ concentration, extracellular signals, electrical coupling, sharing of small metabolites and ions

Front 12

What transmembrane protein is used in both demosomes and adherens?

Back 12

cadherin, difference betwen them is the filament in the cytoplasm that the caherin binds

Front 13

What is the general max size for a molecule going through the gap junction?

Back 13

1 KDa

Front 14

What do integrins do? What type of molecule is it?

Back 14

Connect the extracellular matrix with the cytoskeleton. Either with actin or intermediate filaments

heterodimeric glycoprotein made up of an alpha and beta subunit

Front 15

difference between focal adhesions and hemidesmosomes?

Back 15

FA - actin
Hemi - intermediate filaments

Front 16

What is extracellular ligand binding mediated by?

Back 16

Cations, activation state, dimer, type of ligand

Front 17

Waht do integrins transmit?

Back 17

force and signals

Front 18

What is the difference between outside-in and inside -out integrin activation of integrins?

Back 18

Different ways of being activated

Front 19

What are two imp. function of focal adhesions?

Back 19

withstand force or tension, act as signalling center

Front 20

In cell migration, what will happen if there is integrin-actin connection? and if not?

Back 20

Cell moves, actin polymerization force > retrograde flow
cell does not move, force of actin polymerization is balanced by retrograde flow

Front 21

Do cells migrate toward or away from:
soft substrates?
Stiff substrates?

Back 21

Away from soft, toward stiff

Front 22

What separates connective tissue from non-connective tissue?

Back 22

basal lamina

Front 23

What is an example of non-connective tissue?

Back 23

epithelium

Front 24

What does the highly hydrated porous gel provided by glycosaminoglycans important in?

Back 24

Resisting compressive forces

Front 25

What is the function of fibrous proteins?

Back 25

strength, organization, resilience, cell adhesion
collagen- strength, elastin - rubbery, fibronectin - adhesion, laminin - adhesion

Front 26

What is a major component of glycosaminoglycans? and what is it important for?

Back 26

Hyaluronan (hyaluronic acid)
resisting compressive forces in tissues and joints, important in joint fluid

Front 27

What are proteoglycans composed of?

Back 27

a protein with GAG chains

Front 28

What 2 roles do proteoglycans play?

Back 28

chemical signalling, co-receptors

Front 29

What is the major protein of the extracellular matrix?

Back 29

collagen

Front 30

What does collagen have a lot of?

Back 30

tensile strength

Front 31

Where is the following collagen found?
Types I, II, III, IV

Back 31

I- everywhere
II - cartilage
III - elastic, skin vessels internal organs
IV - basal lamina

Front 32

What are the 2 segments of elastin?

Back 32

hydrophobic - elastic properties
alanine and lysine rich alpha helix, crosslinks between adjascent elastin molecules

Front 33

What are elastin microfibrils composed of?

Back 33

Fibrilling that binds to elastin and is essential for the integrity of the fibers

Front 34

What is a major site for integrin binding?

Back 34

Type III fibronectin repeat (RGD)

Front 35

What does soluble RGD binding compete with for what?

Back 35

Fibronectin for integrin binding

Front 36

What are the 2 structural elements of the basal lamina?

Back 36

1- fibrous proteins, glycoproteins: laminin, collagen IV, nidogen
2- proteoglycans - polysaccaride chains: perlecan

Front 37

What is laminin-1 a primary organizer of? What are its chains held together by?

Back 37

basal lamina
Disulfide bonds

Front 38

What do interruptions in the helical structure of type IV collagen allow?

Back 38

bending

Front 39

What is the main function of proteinases?

Back 39

degrade ECM proteins

Front 40

What is ECM degradation important for?

Back 40

cell division and migration, by proteinases

Front 41

How is proteinase activity regulated?

Back 41

local activation ( secreted inactive precurse which is cleaved by plasminogen activator proteases)
Confinement by proteases cell-surface receptors
Secretion of protease specific inhibitors (TIMPs- Tissue Inhibitors of Metalloproteinases or serpins)

Front 42

What would overexpression of TIMPS cause?
What are MMPs matrix metalloproteases important for?

Back 42

inhibition of cell migration

cell migration

Front 43

What do matrix metalloproteases depend on for activity

Back 43

bound Ca or Zn 2+

Front 44

What does Serpin and TIMPs stand for?

Back 44

serin protease inhibitor
TIMPs - tissue inhibitors of matrix metalloproteinases