Intermediate filaments

Question 1

What makes Intermediate filaments stable?

Answer 1

Helic structure

Question 2

What is unique to IF

Answer 2

They self assemble and require no nucleation

Question 3

T/F IF are much more resistant to strain than actin or microtubules

Answer 3

True

Question 4

What is a structural keratin

Answer 4

Hard apendage (Hair, nail)

Question 5

how is the nuclear lamin disassembly triggered during mitosis

Answer 5

Phosphorylation by a mitotic kinase

Question 6

What structural property of an IF allows for assembly to occur by joining two IF proteins to form a dimer kinked through coiled coil?

Answer 6

Alpha helical rod domains give it tensile strength w/o breaking

Question 7

What two genes are important to IF

Answer 7

Keratin genes and gene Super families.

Question 8

What species group is keratin only found in

Answer 8

Animals

Question 9

Where are keratins found in the stratified epithelium?

Answer 9

the suprabasal layers

Question 10

What two groups are Keratins in IF.

Answer 10

Type I and Type II

Question 11

Which is the most diverse? IF, Actin filaments or microtubules

Answer 11

Intermediate filaments.

Question 12

Where are Type I IF found

Answer 12

Skin, bones, tendon, teeth

Question 13

Where are Type II IF found?

Answer 13

Cartilage and Intravertabrate disks.

Question 14

Where are type III IF found?

Answer 14

Organs, smooth muscle, muscle

Question 15

Where are type IV IF found?

Answer 15

Basal lamina of epithelium

Question 16

Where is desmin found

Answer 16

Muscle

Question 17

Where is vimentin found?

Answer 17

Connective tissue

Question 18

How do Keratins form attachments to cell membranes

Answer 18

By binding to hemidesmosomes and Desmosomes

Question 19

What is unique about Type V IF

Answer 19

They are Lamins found in nucleus and have NLS tails

Question 20

How many types of Keratins are there in humans?

Answer 20

> 50

Question 21

Are Keratins co expressed or independent?

Answer 21

Co-expressed

Question 22

What are properties of Lamins

Answer 22

They are Parallel dimers

Question 23

Where are Type I and II IF mutually found

Answer 23

Epithelial cells

Question 24

What is the most Common IF

Answer 24

Keratin

Question 25

What are the 3 types of Keratin

Answer 25

Simple
Structural
Barries

Question 26

what are Simple keratins?

Answer 26

Proliferate. (blood vessles and intestines

Question 27

what are barrier keratin

Answer 27

Stratified epithelium (skin, glands, esophagus)

Question 28

What are structural Keratin

Answer 28

Hard appendages.

Question 29

How are Keratin structured in epithelial cells

Answer 29

in Sheet like organization

Question 30

Why are antibodies to specific IF important for monitoring cell differentiation in pathology

Answer 30

Keratins can signal a spreading tumor if found in the wrong place.

Question 31

What is the key difference in simple and barrier keratins

Answer 31

Simple keratins only form one layer

Question 32

What causes Epidermolysis bullosa simplex

Answer 32

Mutations of K5 and K14 leads to cell fragility and when ruptured, fluid accumulation

Question 33

What catagory does desmin fall in

Answer 33

Type III

Question 34

Do IF require ATP for growth like other filaments?

Answer 34

No

Question 35

What type of IF is found in specialized structures like hair and nails?

Answer 35

Keratin