Lecture 23: Cell Junctions and Cell Adhesions Flashcards Preview

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Flashcards in Lecture 23: Cell Junctions and Cell Adhesions Deck (61)
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1

How is stress transmitted in epithelial tissue vs connective tissue?

2

4 Types of cell junctions in animal cells?

3

Anchoring Junctions

– Include cell-cell and cell-matrix interactions 

– Transmit external stress from across the plasma membrane to the underlying cytoskeleton 

4

Occluding Junctions

– Form a permeability barrier between cells in an epithelia sheet 

5

Channel forming Junctions

– Create cytoplasmic continuity between adjacent cells for the passage of small molecules

6

Signal Relay Junctions

– Allows extracellular signals to be passed from one cell to another 

– Some anchoring junctions and channel forming junctions also conduct signaling 

7

adherens junctions and desmosomes are ___

cell-cell anchoring junctions

8

actin-linked cell matrix junctions and hemidesmosomes are____

cell-matrix anchoring junctions

9

tight junctions are ___

occluding junctions

10

Gap junctions are ___

channel forming junctions

11

tight junction

seals gap between epithelial cells

12

adherens junction

connects actin filament bundle in one cell with that in the next cell

13

desmosome

connects intermediate filaments in one cell to those in the next cell

14

gap junction

allows the passage of small water-soluble molecules from cell to cell

15

actin-linked cell-matrix junction

anchors actin filaments in cell to extracellular matrix

16

hemidesmosome

anchors intermediate filaments in a cell to extracellular matrix

17

_____ link the cytoskeleton to extracellular structures 

Transmembrane proteins

18

Cell-cell interactions are mediated by the ____ family of transmembrane anchors 

cadherin

19

Cell-Matrix interactions are mediated by the ____ family of transmembrane anchors 

integrin

20

Anchoring Junctions function

• Provide mechanical strength 

– Especially important to tissues encountering severe mechanical stress like heart, muscle, and skin 

• Connect the cytoskeleton to neighboring cells or the extracellular matrix 

21

Anchoring Junctions are composed of what two main classes of proteins?

– Intercellular anchor proteins

– Transmembrane adhesion proteins

22

Types of Anchor Junctions

– Adherens junctions 

– Desmosomes 

– Hemidesmosomes 

– Focal Adhesions 

23

Cadherins 

• Ca2+-dependent cell-cell adhesion

 • Present in adherens junctions and desmosomes 

• Found in virtually all cells and tissues 

24

Cadherin superfamily

25

Cadherins mediate ____ adhesion 

homophilic

26

Cadherin structure and function

27

How do cadherins play a role in development?

Cell with similiar subclasses of cadherins expressed on their surface stick together because of homophilic binding

28

Cadherins mediate cell-cell adhesion by a homophilic mechanism 

• Tissue culture cells (that normally do not express N or E-cadherins) can be made to express either N- or Ecadherin. 

• The resulting population self selects based on homophilic interaction of the individual cadherins

29

Which proteins link cadherins to actin filaments?

  • p-120 catenin
  • Beta-catenin
  • Alpha-catenin
  • vinculin

30