Mmg 409 Final (Ch 19)

Front 1

Folding of the neural tube occurs because of contraction of bundles of _______ ____ __________

Back 1

apical actin filaments

Front 2

Types of cell junctions

Back 2

anchoring

tight

gap

Front 3

Types of anchoring junctions

Back 3

Adherens Junctions (between cells)

Desmosomes (between cells)

Hemidesmosomes (on basal surface aka cell-matrix)

Front 4

AdherensJunctions

Back 4

Connectthe lateral membranes of adjacent epithelial cells.

Found near the apical surface below tight junctions.

It is acircumferential belt of actin and myosin filaments

Acts as a tensioncable that can brace the cell and control its shape.

Front 5

cell adhesion molecules (CAMs)

Back 5

Cells adhere to each other and the extracellular matrixthrough these

Front 6

Inadherens junctions, the main CAM is...

Back 6

Cadherin

Front 7

“Classical”cadherins include (3)

Back 7

E-cadherin (epithelial tissue)

N-cadherin (neural tissue)

P- cadherin (placenta tissue)

Front 8

two major classes of CAMs

Back 8

Homophilic and Heterophilic

Front 9

CAMs associatewith different adaptors, which can either link upto the....

Back 9

microfilaments or

intermediate filaments.

Front 10

CAMs recruit ___ ________ ______ and control ____ ___________.

Back 10

cell signaling proteins

gene expression

Front 11

Main classes of extracellular matrix proteins (ECMs)

Back 11

proteoglycans

collagens

multiadhesive matrix proteins

Front 12

Cadherin adhesion is ____ dependent.

Back 12

Ca++

Front 13

Cell-cell adhesions involve two types ofinteractions:

Back 13

cis (intracellular or lateral interaction)

trans (intercellular interactions)

Front 14

A classical cadherin

Back 14

1 transmembrane domain

N-term extracellular space domain

C-term cytosolic domain

5 extracellular domains

Front 15

Cadherins are regulated by

Back 15

Catenins

Front 16

Cadherins && cancer

Back 16

α-catenin is suppressed in some types of tumors.

When this occurs cells can break free from the tissue and invade the restof the body (metastasis).

Front 17

Regulationof ________ occurs during neural crest cell migration.

Back 17

p120-catenin

Front 18

Desmosomes

Back 18

cell-cell junction

Help transmit shear forces

Providestrength and rigidity

Makeattachments to intermediate filamentsand use desmosomal cadherins as theirCAMs.

Front 19

2 specialized desmosome cadherins

Back 19

desmoglein and desmocollin

Front 20

Hemidesmosomes

Back 20

cell-matrix junction

On the basal surface of epithelial cells.

Attach the cell to the basal lamina using the integrin (α6β4).

Interact with intermediate filaments.

Mainly found in epithelial cells

Front 21

IgCAMs (NCAMs)

Back 21

mediate cell-cell adhesions in neurons

immunoglobulin domains in extracellular

region

homophilic interactions

Not sensitive to Ca++

Front 22

Tight Junctions

Back 22

Seal off body cavities like intestinal lumen and brain to set up body compartments

prevent diffusion of macromolecules and most other molecules

help maintain cell polarity

Front 23

tight junctions are destroyed by

Back 23

the protease Trypsin

Front 24

Tight junction composition

Back 24

Composed of thin bands of plasma membrane

Principal CAMs are occludin and claudin

the proteins have 4 TM domains/helices

Front 25

The C-terminal domain of occludin

Back 25

binds adapter proteins,

which then bind the actin cytoskeleton and

signaling proteins.

Front 26

Integrins

Back 26

CAM used in hemidesmosomes

functions in cell motility, formation, and the regulation of cell life, replication, and death

Front 27

What is the basic structure ofintegrins?

Back 27

heterodimers

α and β subunits contribute to ligand specificity and requiredivalent cations.

Front 28

Are integrins “receptors” or “ligands”?

Back 28

Adhesion receptors for ligands

Front 29

What ECM proteins do integrins bind?

Back 29

fibronectin and laminin

Front 30

What are the two conformations ofintegrins?

Back 30

low affinity state (bent; cytoplasmic C-term tails are bound)

and high affinity states (straight; C-term tails are spread)

Front 31

How is integrin confirmationcontrolled?

Back 31

cell signaling

Front 32

When cells are detached from the ECM or attached to thewrong ECM, they initiate _______.

Back 32

Programmed Cell Death (apoptosis)

Front 33

What is extravasation?

Steps of extravasation

Back 33

leukocyte response to infection/inflammation

1. Rolling

2. Activation

3. Adhesion

4. Trans-endothelial migration

Front 34

How is rolling initiated?

Back 34

Inflammatory signals deliver P-selectin to the surface ofendothelial cells.

Interactions w/ the P-selectin ligand on the leukocytecause them to roll.

Front 35

Leukocyte activation

Back 35

Platelet-activating factor (PAF) is a phospholipid that isalso released from the

endothelium.

It switches the integrins from their low-affinity to highaffinity forms through a G-protein coupled receptor

Front 36

What signal activates integrins?

Back 36

PAF (Platelet-activating factor)

Front 37

Leukocyte Adhesion

Back 37

Integrins bind ICAM and stop rolling.

Front 38

Leukocyte Extravasation

Back 38

leukocytes migrate through the endothelial cells