Cell-Cell Interactions and Cell-Matrix Interactions

Question 1

Zonula occludens

Answer 1

tight seal between epithelial cells so that stuff from outside cannot come inside cell
apical side
runs throughout the entire cell

Question 2

zonula adherens

Answer 2

connects actin filament bundle in one cell with that in the next cell
zips the cells closed

Question 3

desmosome

Answer 3

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

Question 4

gap junction

Answer 4

allows passage of small water soluble molecules from cell to cell- cytosol within cell goes through the gap junction

Question 5

focal junction

Answer 5

actin linked cell matrix adhesion anchors actin filaments in cell to extracellular matrix

Question 6

hemidesmosome

Answer 6

anchros intermediate filaments in a cell to extracellular matrix

Question 7

functions of cell adhesion molecules

Answer 7

structurally link the cell to the outside (other cell or matrix) and they are cell signaling complexes
other proteins can bind in cytoplasmic domain “plaque proteins” seen in structures like desmosomes

Question 8

anchor protein

Answer 8

part of cytoplasmic domain of cell adhesive protein and link the adhesive molecule to cytoskeletal filament

Question 9

cell adhesion molecules

Answer 9

cadherins, immunoglobulin family of CAMs, integrins

Question 10

cadherins

Answer 10

proteins that span membrane; bind to other proteins on cell membrane
requires calcium
structural and signaling roles;

Actin binds to anchor protein, anchor protein binds to cadherin which traverses membrane and binds another cadherin which traverses membrane and binds to anchor porotein and then bind to actin in cytoskeleton
- structurally glued and one cell will respond to mechanical stress of another cell

Question 11

proto-cadherins

Answer 11

link to eachother but not to cytoskeleton

Question 12

IG type of CAM

Answer 12

found in nervous system, in synapses

Question 13

integrins

Answer 13

alpha and beta subunit form a dimer which will bind to ECM
predominantly laminin or fibronectin (RGD domain);
bind to cytoskeleton

Question 14

types of binding

Answer 14

homophilic- bind to identical proteins expressed by neighboring cell heterophilic- bind to proteins from same family but different genes
or
bind to extra cellular matrix

Question 15

zonula occludens

linker transmembrane protein

Answer 15

claudin, occludin, JAM-1 (junctional adhesion molecule)

Question 16

Zonula occludens intracellular plaque protein

Answer 16

ZO1, 2, 3

Question 17

Zonula occludens filament

Answer 17

actin

Question 18

ZOT

Answer 18

zonula occludens toxin
binds to receptor on surface of cell and is transported into cell by cell’s endocytotic mechanism
alter cellular signaling and lead to disassembly of zonula occludens
bacteria can invade host epithelia and increase movement of water into lumen of gut–> diarrhea
cholera is example

Question 19

zonula adherens

Answer 19

fascia adherens
circles entire cell
larger distance between membranes- junction has cadherin which goes through membrane and binds to protein in cytoplasm;
provide structure and strength to tissue and barriers to movement between cells

Question 20

zonula adherens linker transmembrane

Answer 20

cadherin

Question 21

zonula adherens intracellular plaque protein

Answer 21

cell signaling: alpha, beta, gamma catenin; skeletal components: vinculin and alpha actinin

Question 22

zonula adherens filament

Answer 22

actin

Question 23

desmosomes

Answer 23

spot welds;

cadherin binding to plaque protein binding to keratin

Question 24

macula adherens linker transmembrane

Answer 24

desmosome;

linker is cadherin (desmocollins and desmoglein)

Question 25

macula adherens intracellular plaque protein

Answer 25

anchor proteins [plakophilin–plakoglobin (gamma-catenin)]–desmoplakin

Question 26

macula adherens filament

Answer 26

intmdt filaments (keratin)

Question 27

gap junctions

Answer 27

hole between cells allowing for free diffusion of ions
made up of six connexin proteins that form a hemi-pore on one membrane which will line up with hemipore on another membrane and form a pore

Question 28

size of molecules which can pass through gap junctions

Answer 28

1400 daltons

ATP, calcium, small proteins, etc

Question 29

hemidesmosome

Answer 29

spot weld at bottom of the cell that connects cell with extracellular matrix in the basal lamina

Question 30

what proteins are targeted in Bullous pemphigoid?

Answer 30

BP180-membrane spanning complex

and BP230- attaches to keratin

Question 31

linker transmembrane for hemidesmosome

Answer 31

integrins (alpha6 and beta4)

binds to laminin in ecm

Question 32

intracellular plaque protein hemidesmosome

Answer 32

plectin, BP230

Question 33

filament hemidesmosome

Answer 33

intermediate filament

Question 34

focal adhesion

Answer 34

mechanical and signaling complex

Question 35

linker transmembrane for focal adhesion

Answer 35

integrins

Question 36

intracellular plaque protein for focal adhesion

Answer 36

talin, vinculin, alpha-actinin, FAK (focal adhesion kinase), src kinase, Ras, Raf, Grb2, SoS

Question 37

filament for focal adhesion

Answer 37

actin

Question 38

mechanical stress does what to focal adhesion

Answer 38

mechanical stress results in activation of kinases associated with focal adhesion–> activate MAP kinase pathway and signal nucleus to upregulate formation of adhesion and lead to actin meshwork formation