Intermediate Filaments Flashcards
What are three types of protein filaments?
Protein filaments, actin filaments, microtubules.
Does each type of filaments have a different mechanical properties?
Yes
Different subunit??
Yup
Intermediate filaments characteristics
Strong, ropelike ,long strands twisted together to provide tensile strength
Subunits?
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.
Where are they found?
Cytoplasm
Nuclear lamins - in nucleus
What do they form?
They form a network surrounding the nucleus and extending out to the cell periphery.
They strengthen cells against.. ?
Mechanical stress
They are often anchored to cell membrane ..?
Cell-cell junction
Called .. :)
Desmosomes
What do they also form?
A mesh work called nuclear lamina
What does nuclear lamina do?
It underlies and strengthen the nuclear envelope
How many classes can intermediate filaments be grouped into?
4 classes
Name them queen!
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)
What is the most diverse intermediate filament
Keratin
Where is keratin found?
In every kind of epithelium in vertebrae body
These filaments are indirectly connected through..?
Desmosomes
The filaments associate laterally with cell components throughout.. ?
Phospholipids
Keratin function>
Distributes the stress that occurs when skin is stretched.
Nuclear lamina is from
Lamins
It disassembles and reforms at every cell division
Yes/no?
Yessss
When ?
When the nuclear envelope breaks down during mitosis and then reforms in each daughter cell.
What controls the disassembly and reassembly of nuclear lamina?
Phosphorylation and de-phosphorylation
Lamins phosphorylate —>
Conformational change weakens the binding between the lamin tetramers—> they fall apart
Dephosphotylation?
Lamins reassemble
What are hemidesmosomes
They mediate adhesion between basal cells of epithelial tissues and substratum
