Cell Junctions

Question 1

Selectins-structure and function

Answer 1

Transmembrane proteins that bind oligosaccharides (CAD domain) and Ca2+, important in Homing process

Question 2

Tight Junction 2 Functions

Answer 2

Pore, Barrier

Question 3

Focal Adhesions-mediated by

Answer 3

Integrins

Question 4

Belt Desmosomes (Zona Adherens)-mediated by

Answer 4

Cadherins

Question 5

Claudins-Function

Answer 5

Regulate paracellular permeability of ions

Question 6

Hemidesmisomes-location and function

Answer 6

Found on basal surface (mediate interaction of cells and basement membrane)

Question 7

Spot Desmosomes (macula Adherens)-mediated by

Answer 7

Desmoglein, Desmocollins

Question 8

Belt Desmosomes–Cadherin adhesion molecule—cytoskeleton

Answer 8

Cadherin: transmembrane adhesion molecules that mediate adhesion in the belt Desmosome
Cadherins are attached to the actin cytoskeleton via Catenins

Question 9

Spot Desmosomes-structure/function

Answer 9

Dense plaques (Desmoplakin, plakoglobin) with Int. Fils (keratin) coming off 
-cell-cell junctions

Question 10

Integrins-interaction with ECM proteins

Answer 10

Via RGD peptide sequences

Question 11

Connexons-structure and function

Answer 11

Made of 6 Connexin proteins, link up to other cell Connexon to create hydrophilic channel for ions to pass through (cell-cell communication)

Question 12

Blistering Diseases (2)

Answer 12

1. Pemphigus Foliceas

2. Bulbous Pemphigoid

Question 13

Focal Adhesions, function and visualization

Answer 13

help with cell migration, visualized best via immuno-EM

Question 14

Hemidesmisomes (mediated by)

Answer 14

Integrin a6B4

Question 15

Spot Desmosomes- cytoskeleton

Answer 15

Intermediate filaments

Question 16

Gap Junctions-formed by

Answer 16

Connexons

Question 17

Cadherins: 1. Which junction? 2. Depends on? 3. Two Examples and their related diseases

Answer 17

1. Belt Desmosomes
2. Need calcium to function
3. E-Cadherin: cell-cell adhesion in epithelia (loss=Epithelial Mesencyhmal Transition, EMT, in cancer progression)
   P-Cadherin: Select tissues (hair, retina) show issues if mutated

Question 18

Two key IgCAMs (homing)

Answer 18

ICAM and VCAM

Question 19

Tight Junctions-cytoskeleton

Answer 19

Actin via adaptor proteins (ZO-1)

Question 20

ClaudinS 16/19

Answer 20

Regulate kidney perm to Ca and Mg (dysfunction-misreuptake of those ions)

Question 21

Integrins- location and structure

Answer 21

Transmembrane proteins that bind to ECM proteins and Cytoskeleton 
Two subunits (a and B)

Question 22

IgCAMs- structure and function

Answer 22

EC domain-Ig-like, Ca+ independent, are adhesion molecules

Question 23

Integrins- interaction with cytoskeleton

Answer 23

Interact with actin-linked cell matrix adhesions sites (focal adhesions)

Question 24

Leukocyte Extravision Process-What is on the surface of the endothelial cells?

Answer 24

Selectins-adhesion to slow down Leukocytes at first

ICAM, VCAM-to bind to Integrins on Leukocytes to arrest their movement

Question 25

Hemidesmisomes-cytoskeleton

Answer 25

Interact via intermediate filaments

Question 26

Focal Adhesions-cytoskeleton

Answer 26

Linked to actin filaments of cytoskeleton

Question 27

Leukocytes Extravision Process- What are on the Leukocytes?

Answer 27

Integrins

Question 28

Bullous Pemphigoid

Answer 28

Caused by mutation that impacts hemidesmisome adhering molecules Blisters form between basal layer of epithelia and basement membrane

Question 29

Leukocyte Extravision Process

Answer 29

1. Leukocytes slow and being to ROLL on endothelial surface due to loose adhesion with Selectins on endothelial surface 2. Integrins on Leukocytes are activated and bind ICAM and VCAM on endothelial cell surface 3. Leukocytes are arrested on endothelial cell surface 4. Integrin-mediated migration of Leukocytes through wall of blood vessels (in between endothelial cells) occurs

Question 30

Tight Junctions- mediators

Answer 30

Occludins, Claudins

Question 31

Pemphigus Foliceas

Answer 31

Caused by mutation in adhering molecule of Spot Desmosomes (desmigleans) Blisters in between layers of epithelia

Question 32

Connexon permeability

Answer 32

Regulated by many factors (voltage, Ca, pH, etc.)

Question 33

Dynamic Adhesions (2)

Answer 33

1. Selectins | 2. IgCAMs

Question 34

Catenins

Answer 34

Link Cadherins (belt Desmosomes) to actin cytoskeleton