Tissue Architecture

Question 1

What are the three types of cytoskeleton filaments?

Answer 1

1. Intermediate filaments
2. Microtubules
3. Microfilaments

Question 2

Describe intermediate filaments

Answer 2

• great tensile strength, can withstand mechanical stress
• found in the cytoplasm
• often anchored to plasma membrane at cell-cell junctions
• form the nuclear lamina
• rope like properties
• alpha helical monomer»coiled-coil dimer» staggered tetramer of two coil dimers.
• lateral association of 8 tetramers

Question 3

Progeria is associated with the dysfunction of what cytoskeletal molecule

Answer 3

Intermediate filaments!

They make up the nuclear lamina.
Defective nuclear lamina results in early aging»>progeria

Question 4

Describe microtubules

Answer 4

• form long stiff hollow tubes.
• rapidly assemble and disassemble
• create tracks for transport vesicles
• form mitotic spindle
• made of alpha+beta subunits.
• plus end grows faster than minus end.
• nucleating cites (y-tubulin) makes tubes form

Question 5

Describe micro filaments

Answer 5

• present in f form, filament
• present in g form, globular.
• present in all cells
• unstable, need association with other proteins to be helpful
• essential for cell movement

Question 6

Describe collagen

Answer 6

• Main structural protein in ECM.
• 28 types
• trimeric proteins
• associate as fibers, sheets, or transmembrane structures
• need iron and ascobate to hydroxylase collagen.

Question 7

Cadherin superfamily

Answer 7

• ca2+ dependent
• at demosomes and adheren junctions
• interact with actin
• expressed in different places in the body

Question 8

Types of cadherin

Answer 8

E-cadherin: epithelial
N-cadherin: neural
VE-cadherin: vascular-endothelial
LI-cadherin: liver-intestine

Question 9

Cadherins can serve as biomarkers for what?

What is an example?

Answer 9

For invasive/metastatic tumors

Decreased expression of E-cadherin in transitional bladder cancer and an increase in N-cadherin.

Question 10

Ig Superfamily CAMs

Answer 10

• calcium independent transmembrane glycoproteins
• expressed on the vascular side of endothelial cells.
• involved in recognition, binding, or adhesion

Question 11

Selectins

Answer 11

• Calcium dependent
• bind to extracellular carbohydrates
• important role in local inflammatory response
• low affinity for ligands, allows for leukocyte “rolling”

Question 12

Integrity

Answer 12

• higher affinity for ligand, allows for leukocytes to squeeze in.
• binds extracellular matrix to cytoskeleton.