Tissue Architecture

Question 1

What type of cytoskeletal filaments are responsible of protecting cells from mechanical stress?

Answer 1

Intermediate Filaments

Question 2

What is the name of the “mesh-like” structure that strengthens the nuclear envelope?

Answer 2

Nuclear Lumina

Question 3

What causes Ehlers-Danlos Syndrome? What does it affect?

Answer 3

Caused by a mutation in the collagen or the collagen synthesis genes.

It weakens connective tissues in the skin, organs, bones, and blood vessels.

Question 4

What is the function of focal contacts? What is their role?

Answer 4

To link cells to the extracellular matrix of basal lamina.

Roles in migration, immune system function, wound healing, tissue architecture.

Question 5

What are the 2 subtypes of Cadherin superfamily? Give examples of each and state their role

Answer 5

1. Classic Cadherins: Type 1: E, N, R-cadherin
   Type 2: VE cadherin
   Both are linked to actin cytoskeleton; associated with adherens junctions
2. Atypical Cadherins: T, LI-cadherins: function as hemophiliac adhesion proteins with interaction with catenins or link to actin cytoskeleton.

Question 6

Enumerate the cytoplasmic Intermediate Filaments:(3) and where they would be located

Answer 6

Keratin filaments: in epithelial cells
Vimentin filaments: in connective-tissue cells, muscle cells, and glial cells
Neurofilaments: in nerve cells

Question 7

What is Progenia and what causes it?

Answer 7

Progenia is an accelerating aging disease.

It is caused by a mutation in the Nuclear Lamina.

Question 8

On which tubulin is the “+” end located?

Answer 8

Beta-tubulin

Question 9

What does the chemotherapeutic drug Taxol target/do?

Answer 9

it binds and stabilizes microtubules (therefore chromosome segregation is inhibited)

Question 10

Action of Colchicine

Answer 10

Binds tubulin dimers and prevents their polymerization.

Question 11

Action of Vinblastine

Answer 11

Binds tubulin dimers and prevents their polymerization.

Question 12

What is the action of Phalloidin?

Answer 12

It binds and stabilizes filaments.

It also helps visualize actin filaments.

Question 13

What are the functions of ECM(Extracellular Matrix)? (6)

Answer 13

1. Anchoring and engulfing cells to define tissue boundaries.
2. Determining the biomechanics properties
3. Controlling cellular polarity, survival, proliferation, differentiation
4. Inhibiting or facilitating cell migration.
5. Binding to and acting as a reservoir of growth factors
6. Serving either directly as a ligand for signaling receptors.

Question 14

How is Collagen formed?

Answer 14

a C-terminal propertied initiates the triple helix formation in the rough ER. Procollagen in secreted in the extracellular place. Enzymes cleave propertied to form collagen.

Question 15

Cadherins can serve as biomarkers for?________

Answer 15

invasive, metastatic tumors.
EMT(Epithelial to Mesenchymal Transition).
In transitional bladder cancer there is a decrease in E-cadherins and an increase in N-cadherins.

Question 16

Enumerate few functions of Ig CAMs

Answer 16

Immune cell interactions
expression vascular endothelial cells and bind to various integral molecules
Involved in recognition, binding, and adhesion processes of cells.

Question 17

Which CAM family has low affinity to ligands and allow for leukocytes “rolling” during leukocytes adhesion cascade?
(they are calcium dependent glycoproteins)

Answer 17

Selectins. They also bind to extracellular carbohydrates and play important rollin host defense mechanism.

Question 18

Which CAM family has higher affinity to leukocytes and allows for adhesion (causing them to stop) and transmigration to site of infection?

Answer 18

Integrins. (cell-cell interaction via BETA2 family).

Question 19

in which type of cells are keratin filaments located?

Answer 19

Epithelial cells.