Intermediate Filaments

Question 1

What are three types of protein filaments?

Answer 1

Protein filaments, actin filaments, microtubules.

Question 2

Does each type of filaments have a different mechanical properties?

Answer 2

Yes

Question 3

Different subunit??

Answer 3

Yup

Question 4

Intermediate filaments characteristics

Answer 4

Strong, ropelike ,long strands twisted together to provide tensile strength

Question 5

Subunits?

Answer 5

Fibrous subunits each containing a central elongated rod domain consists of an extended alpha helical region that enables pairs of intermediate filament proteins to form stable dimers by wrapping around each other in a coiled-coil dimers running in opposite directions forming a staggered tetramer.

Question 6

Where are they found?

Answer 6

Cytoplasm
Nuclear lamins - in nucleus

Question 7

What do they form?

Answer 7

They form a network surrounding the nucleus and extending out to the cell periphery.

Question 8

They strengthen cells against.. ?

Answer 8

Mechanical stress

Question 9

They are often anchored to cell membrane ..?

Answer 9

Cell-cell junction

Question 10

Called .. :)

Answer 10

Desmosomes

Question 11

What do they also form?

Answer 11

A mesh work called nuclear lamina

Question 12

What does nuclear lamina do?

Answer 12

It underlies and strengthen the nuclear envelope

Question 13

How many classes can intermediate filaments be grouped into?

Answer 13

4 classes

Question 14

Name them queen!

Answer 14

1.Keratin filaments in epithelial cells.(cytoplasm)
2.vimentin related and vimentin filaments in connective tissue ,muscle, supporting cells in nervous system(cytoplasm)
3.neurofilaments in nerve cells.(cytoplasm)
4. Nuclear lamina which strengthen the nuclear envelope.(nucleus)

Question 15

What is the most diverse intermediate filament

Answer 15

Keratin

Question 16

Where is keratin found?

Answer 16

In every kind of epithelium in vertebrae body

Question 17

These filaments are indirectly connected through..?

Answer 17

Desmosomes

Question 18

The filaments associate laterally with cell components throughout.. ?

Answer 18

Phospholipids

Question 19

Keratin function>

Answer 19

Distributes the stress that occurs when skin is stretched.

Question 20

Nuclear lamina is from

Answer 20

Lamins

Question 21

It disassembles and reforms at every cell division
Yes/no?

Answer 21

Yessss

Question 22

When ?

Answer 22

When the nuclear envelope breaks down during mitosis and then reforms in each daughter cell.

Question 23

What controls the disassembly and reassembly of nuclear lamina?

Answer 23

Phosphorylation and de-phosphorylation

Question 24

Lamins phosphorylate —>

Answer 24

Conformational change weakens the binding between the lamin tetramers—> they fall apart

Question 25

Dephosphotylation?

Answer 25

Lamins reassemble

Question 26

What are hemidesmosomes

Answer 26

They mediate adhesion between basal cells of epithelial tissues and substratum