Cell Junctions and Adhesion Flashcards Preview

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Flashcards in Cell Junctions and Adhesion Deck (68):
1

Cell junctions are best observed in

Epithelial cells

2

What are the types of cell junctions?

1.) Tight junctions
2.) Zonula adherens (belt desmosomes)
3.) Macular adherens (spot desmosomes)
4.) Hemidesmosome
5.) Gap (communicating) junctions

3

Define cell polarityand control the passage of substances between adjacent cells

Tight junctions

4

Have a distribution like a ribbon internally bracing the cells and are associated with actin filaments

Tight junctions

5

An anchorage junction that has a beltlike distribution and is associated with actin filaments

Zonula adherens (belt desmosome)

6

An anchorage junction with a spotlike distribution and is associated with intermediate filaments

Macula Adherens (spot desmosomes)

7

Link the basal domain of an epithelial cell to the basal lamina. Intermediate filaments are associated with a plaque

Hemidesmosome

8

Connect functionally two adjacent cells.

-Formed by connexons

Gap junction

9

Channel-like structures that enable the passage of small molecules

Connexons

10

Gap junctions are not associated with

Cytoskeletal components

11

What are the two cell-cell anchorage junctions?

Belt desmosomes and spot desmosomes

12

What are the cell matrix junctions?

Hemidesmosomes and focal adhesions

13

The transmembrane proteins for the cell-cell anchor junctions (belt and spot desmosomes) are?

Cytoskeletal?

1.) Cadherins

Actin (belt)
Intermediate filaments (spot)

14

Which two proteins make up tight junctions?

Occludins and Claudins

15

Encircle the entire cell like a belt

Tight junctions

16

The apical domain of a cell faces the

Lumen

17

Tight junctions are composed of “sealing strands” where the two membranes are tightly linked together by lines of

Transmembrane proteins

18

Mediate the adhesion at tight junctions

Occludins and Claudins

19

Occludins and claudins are linked to the actin cytoskeleton through adaptor proteins like

ZO-1

20

Also encircle the entire cell an are positioned right underneath the tight junctions

Belt desmosomes

21

Transmembrane proteins that mediate adhesion at the belt desmosomes

Cadherins

22

In order to function, cadherins need

Calcium

23

Cadherins are linked to the actin cytoskeleton by

Catenins

24

Catenins are made up of

α, β, and ƴ/plakoglobin

25

Binds to cadherin and ƴ-catenin/plakoglobin

β-catenin

26

Binds directly to actin

α-catenin

27

The main proteins holding epithelial cells together in a sheet

Cadherins

28

Important for cell-cell adhesion in the epithelia

E-cadherin

29

Contributes to epithelial-mesenchymal transition (EMT) during cancer progression

Loss of E-cadherin

30

E-caherin engagement is needed for

Tight junction formation

31

Spot-like cell-cell junctions

Spot Desmosomes

32

Cadherin family proteins that mediate the adhesion at spot desmosomes

Desmocollins and desmogleins

33

Spot desmosomes are linked to which cytoskeletal component?

Intermediate filaments

34

Transmembrane proteins that have an α subunit and a β subunit.

-interact with extracellular matrix proteins on the RGD peptide sequence

Integrins

35

Integrins are present in actin-linked cell-matrix adhesion sites called

Focal adhesions

36

Mediate the interactions between the cells and the basement membrane

Hemidesmosomes

37

Mediates the interaction between hemidesmosomes and the basement membrane

Integrin α6β4

38

Hemidesmosomes are linked to which cytoskeletal component

Intermediate filaments

39

Integrin mediated and are linked to the actin cytoskeleton. These adhesions are not visible under conventional EM, but can be visualized using immuno-EM.

Focal adhesions/focal contacts

40

Focal adhesions/focal contacts are important for many cellular processes including

Cell migration

41

Serve to coordinate cellular responses

Gap junctions

42

Formed by connexon channels, which allow small molecules like Ca2+ and cAMP to pass from cell to cell

Gap junctions

43

Connexons are formed by six connexin proteins. Connexon on cell A interacts with connexon on cell B to form the

Hydrophilic chanel

44

Connexon permeability is regulated by multiple factors including

pH, Voltage, Calcium, etc

45

In gap junctions, there are two plasma membranes close together, similar to tight junctions. However, unlike tight junctions, gap junctions can be

Very extensive structures

46

Small molecules can pass between cells through gap junctions. Gap junctions are abundant in

Cardiac, smooth muscle, and epithelial cells

47

In connexon channels, high calcium concentration signals

Apoptosis

48

Claudin 16 mutation causes an autosomal-recessive renal disorder, familial hypomagnesemia with hypercalciuria and nephrocalcinosis. This affects

Tight Junctions

49

P-cadherin mutation causes hypotriosis with juvenile
macular dystrophy, characterized by early hair loss and
progressive degeneration of the central retina. This affects

Belt desmosomes

50

Autoimmune disease with antibodies against Desmoglein such as 1-blistering disease affects

Spot desmosomes

51

Autoimmune disease with antibodies against BPAG1 such as 2-blistering disease affects

Hemidesmosomes

52

Mutations in multiple different connexins causes defects in gap desmosomes that are assoicated with which clinical phenomenon?

Deafness

53

There are different ways to get blistering diseases. Blistering diseases are caused by defects in either

Spot desmosomes or hemidesmosomes

54

Will cause splitting (vesicles) within the epidermal cell layers

Spot desmosome defects

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Will cause splitting (vesicles) between the epidermis and the underlying basement membrane

Hemidesmosome defects

56

Usually found during cell locomotion where dynamic cell-cell and cell-matrix adhesions are needed

Non-junctional adhesions

57

Cell adhesion does not only happen at stable cell junctions. During cell locomotion, we also need

Dynamic adhesions

58

Transmembrane proteins that bind oligosaccharides

-calcium dependent

Selectins

59

Selectins are expressed on the surfaceof

Lymphocytes (L-selectin), endothelial cells (E-selectin), and platelets (P-selectin)

60

The extracellular segment of cell adhesion molecules (CAMs) are folded into 2-6 immunoglobin-like domains. As a result, CAMs belong to the

Immunoglobin (Ig) Superfamily

61

Immunoglobulin superfamily cell adhesion molecules (IgCAMs) have Ig-like domains on the

Extracellular side

62

IgCAMS are NOT dependent on

Calcium

63

Play important roles in T cell interactions and binding of leukocytes to activated or resting endothelial cells

ICAM and VCAM

64

Slow down and start rolling on the endothelial cell surface through loose adhesion with selectins on the
endothelial cell surface

Leukocytes

65

During rolling, integrins on the leukocytes are activated to bind to

ICAM and VCAM on endothelial surface

66

These stronger adhesive interactions lead to the arrest of leukocytes on the endothelial cell surface, and the subsequent integrin-mediated migration of leukocytes through the wall of the blood vessel, in between the

Endothelial cells

67

The lymphocyte-endothelial cell interaction requires which two types of cell adhesion proteins?

Selectins and Integrins

68

High Endothelial Venules (HEVs) in the deep cortex and medulla of lymph nodes allow for the transition of lymphocytes from the blood stream to

Lymph Tissue

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