Cell Adhesion Flashcards Preview

Physiology Exam 3 > Cell Adhesion > Flashcards

Flashcards in Cell Adhesion Deck (46):
1

Functions of cell-to-cell interactions

1. Wound healing
2. Inflammation response
3. Immune response (self vs. non-self recognition)
4. Tumor metastasis
5. Blood clotting
6. Growth and development

2

Cell adherence is?

Specific and reversible

3

2 types of cell adherence

1. Homotypic adhesion
2. Heterotypic adhesion

4

Cell-cell interactions are dependent on?

1. Cell-cell recognition
2. Cell-cell adhesion → allows for communication

5

Cadherins need ____ to function, which is to:

Require calcium

Allow interaction with neighboring cell via cadherins of same time

6

Cadherin adhesion

Homotypic adhesion → bind through adherens junctions (actin cytoskeleton, desmosomes)

7

Integrins are?

Linker proteins (link ECM components and cell)

8

Types of cell junctions

1. Adhesive (anchoring)
2. Tight
3. Gap

9

Adhesive (anchoring) junctions

Links cells in tissues by connecting cytoskeletons → allows cells to function as unit and share stress

10

Adhesive junctions are prominent in?

Cells subjected to high stress;
1. Skin
2. Bladder
3. Heart
4. Stomach

11

Adhesive junction types

1. Desmosomes
2. Hemidesmosomes
3. Adherens junction

12

All adhesive junctions contain 2 distinct types of proteins. What are they?

1. Intracellular attachment proteins (inside plasma membrane)
2. Transmembrane linker proteins (outside plasma membrane → bind cells to ECM)

13

Desmosome adhesion

Between cells (linker proteins)

Provides structural integrity (resists stress)

14

Desmosomes are in what kind of cells?

Squamous epithelial and muscle cells

15

Desmosomes are abundant in what types of tissues?

1. Heart
2. Skin
3. Neck of uterus

16

Hemidesmosomes connect

Epithelial cell to basal membrane (plaque only in 1 cell)

17

2 types of adhesive junctions

1. Adhesion belt
2. Focal contact

18

Adhesion belts

Are:

Common in:

Connection:

Encompass entire cell

Common in layer of tissue that line body cavities

Connect to cytoskeleton and adjacent cell via actin

19

Focal contact

Attach cells to ECM

Not continuous

Use integrins

20

What are connexons?

Hollow cylinders → special type of protein composed of assembly of 6 connexin subunits

21

Gap junctions are abundant in tissue with what requirements?

Rapid communication (muscle and nerve)

22

What do gap junctions facilitate in the heart?

Flow of electrical current

23

Where are gap junctions in the brain?

Cerebellum → facilitates rapid muscle movements

24

Tight junctions

Leave NO space between plasma membranes of adjacent cells → prevents movement of fluids and ions between cells (or of 2 different body compartments)

25

Tight junction with the least amount of sealing are found where?

Bladder

26

Tightest tight junctions in the body

Epithelial cells of inner ear

27

Function of blood-brain barrier derives largely from?

Tight junctions

28

How is the efficiency of a tight junction regulated?

Number of independent sealing strands

29

Major proteins in sealing strands of tight junctions

Claudins and occuludin

30

What are sealing strands in tight junctions formed from?

Row of transmembrane proteins embedded in both plasma membranes

Extracellular domains join one another directly

31

Tight junctions joint together the ______ of adjacent cells

Cytoskeleton

32

Pemphigus

Autoimmune disorder which produces antibodies against cadherins

Skin gets attached by immue system and looks fucked up (lots of blisters and such)

33

Natalizumab

Anti-integrin antibodies (attached alpha 4-integrin)
Used to treat MS (multiple sclerosis) and IBD (inflammatory bowel disease)

34

Cadherins do what type of cell adhesion?

Homotypic (especially epithelia)

35

Cadherins bind through

Adherens junction: actin cytoskeleton + desmosomes

36

Desmogelins

Type of cadherin, targeted by pemphigus

37

Most common immune mediated skin disease in dog and cat

Pemphigus foliaceus

38

alpha 4-integrins

Important for recruitment of lymphocytes ad monocytes to inflammation sites

39

Homotypic adhesion

Adherence of cell to similar cell

(Ex: epithelial cells in epithelial sheet)

40

Heterotypic adhesion

Adherence of cell to dissimilar cell

(Ex: neuron + Schwann cell, neutrophil + endothelial cell)

41

Cadherin location

Plasma membrane of most cells

42

Cadherin side chains

Carbohydrate side chains (affect strength and specificity)

43

Intracellular attachment proteins

Attach adhesive junction to cytoskeleton filaments (inside plasma membrane)

44

How do intracellular attachment proteins attach adhesive junction to cytoskeleton filaments?

Form thick plaque on cytoplasmic side of plasma membrane

45

How do connexins form gap junctions?

2 hemichannels/connexins from opposing cells stick together to form intercellular gap junction channel

46

Why are integrins "linker" and no "adhesive" proteins?

Weak binding → low affinity allows for exploration of environment → prevents "gluing" of cell to ECM