BI203 Lecture 20: Extracellular Matrix and Cell-Cell Interactions - Slides 1-15

Question 1

Each organ = millions-billions of cells
held together & organized by:

1) ___ ___ (ECM) Interactions.
2) ___ Interactions.

Answer 1

Cell-Extracellular Matrix Interactions, Cell-Cell Interactions

Question 2

The ___ ___ (ECM) is composed of a complex mixture of proteins (collagen) and polysaccharides.

Answer 2

Extracellular Matrix

Question 3

___ play a key role in tissue maintenance and repair by secreting and maintaining the Extracellular Matrix.

Answer 3

Fibroblasts

Question 4

The Extracellular Matrix (ECM) is composed of a complex mixture of ___ (collagen) and ___.

Answer 4

proteins, polysaccharides

Question 5

Most ___ cells are embedded in an extracellular matrix.

Answer 5

animal

Question 6

Extracellular matrix is most abundant in ___ tissues.

Answer 6

connective

Question 7

___ ___: thin layers on which epithelial cells rest. Also surrounds muscle cells, adipose cells, and peripheral nerves.

Answer 7

Basal laminae

Question 8

___ ___ (loose connective tissue, bone, tendon, and cartilage) consist mostly of extracellular matrix with cells distributed throughout.

Answer 8

connective tissues

Question 9

Cells have ___ ___ proteins that attach to the ECM.

Answer 9

cell surface proteins

Question 10

___ - Transmembrane proteins that attach cells to the extracellular matrix.

Answer 10

integrins

Question 11

Integrins function as heterodimers of ___ & ___ subunits.

Answer 11

a, b

Question 12

Integrins function as ___ of a & b subunits.

Answer 12

heterodimers

Question 13

Differences in ___ ___ sequences leads to differences in ECM component interactions.

Answer 13

extracellular domain sequences

Question 14

Differences in extracellular domain sequences leads to differences in ___ ___ interactions.

Answer 14

ECM component interactions

Question 15

They are heterodimers; different combinations of subunits result in ___ different integrins.

Answer 15

24

Question 16

Integrins bind to various components of the ___, including collagen, fibronectin, and laminin.

Answer 16

ECM

Question 17

Integrins were first identified by immunofluorescence and immunoelectron microscopy of ___ ___ at points of cell adhesion to the matrix.

Answer 17

transmembrane glycoproteins

Question 18

Integrins also anchor the ___ to the ECM.

Answer 18

cytoskeleton

Question 19

___ types of cell-matrix junctions.

Answer 19

2

Question 20

Two types of cell-matrix junctions:

Answer 20

focal adhesions, hemidesmosomes

Question 21

___ ___ domains of integrins interact with ECM components.

Answer 21

large extracellular domains

Question 22

___ ___ domains of integrins interact with the cytoskeleton.

Answer 22

small intracellular domains

Question 23

Integrins’ interactions with the cytoskeleton provide ___ ___ to the cell-ECM interaction.

Answer 23

structural strength

Question 24

___ ___ - Bundles of actin filaments are anchored to β subunits of integrins via other proteins: α-actinin, talin, and vinculin.

Answer 24

focal adhesions

Question 25

Focal adhesions - Bundles of actin filaments are anchored to B subunits of integrins via other proteins: ___, ___, and ___.

Answer 25

a-actinin, talin, vinculin

Question 26

___ anchor epithelial cells to basal laminae.

Answer 26

hemidesmosomes

Question 27

Hemidesmosomes anchor ___ ___ to ___ ___.

Answer 27

epithelial cells, basal laminae

Question 28

α6β4 integrins link basal lamina layer of the extracellular matrix to intermediate filaments via ___.

Answer 28

plectin

Question 29

Most Cell-Cell Interactions are Mediated via ___.

Answer 29

cadherins

Question 30

___ ___ = Cell-cell interactions mediated by cadherins linked to the actin cytoskeleton within adjacent cells.

Answer 30

adherens junctions

Question 31

Adherens junctions = Cell-cell interactions mediated by ___ linked to the ___ cytoskeleton within adjacent cells.

Answer 31

cadherins, actin

Question 32

Adherens junctions link ___ ___ of adjacent cells.

Answer 32

actin filaments

Question 33

Desmosomes link ___ ___ of adjacent cells.

Answer 33

intermediate filaments

Question 34

___ link intermediate filaments of adjacent cells.

Answer 34

Desmosomes

Question 35

___ ___ = cell-cell interactions through open membrane channels.

Answer 35

Gap junctions

Question 36

Gap junctions = cell-cell interactions through ___ membrane channels.

Answer 36

open

Question 37

Gap junctions allow the free passage of ___ & small ___ b/w connected cells. They also enable rapid ___ & coupling of ___ activities.

Answer 37

ions, molecules, communication, metabolic

Question 38

Gap junctions also allow passage of signaling molecules, such as ___ and ___, potentially coordinating responses of cells in tissues.

Answer 38

cAMP, Ca2+

Question 39

___ ___ in epithelial cell sheets form a seal that prevents free passage of molecules and ions between cells.

Answer 39

Tight junctions

Question 40

Tight junctions provide minimal adhesive strength between the cells, so they are usually associated with adherens junctions and desmosomes in a ___ ___.

Answer 40

junctional complex