Intermediate Filaments Flashcards
Are intermediate filaments polar
No they don’t have + or - ends
What are intermediate filaments
They are strong flexible unbranched fibres that are only found in animal cells
The give mechanical strength to neurons, muscle cells, epithelial (keratin) cells
They are chemically heterogenous (meaning their made up of diverse protiens)
Has five classes
How are intermediate filaments first made
First you have a monomer (just peptide) with globular heads
This monomer binds to another to from a dimer
The dimer bind with another dimer to form a tetramer, the ends are CN and CN so no polarity since their identical
How are intermediate filaments made after the tetramer is formed
8 of the tetramers come together to make a unit length of the intermediate filament which is about 60nm in size
The many unit lengths come together to make the intermediate filament through strong lateral interactions
How do unit lengths of intermediate filaments get replaced
How does this occur
One unit length is added to middle of the filament and at the same time one unit length is kicked out
This is controlled by the phosphorylation status of the unit length, NO ATP OR GTP involved
In relation to intermediate filaments, how to they make the cells more stable
A bridging protein (plectin) can bind other components in the cell to an intermediate filament to increase the cells stability
What are intermediate filaments in neurons called
Neurofilaments
What do neurofilaments do
Their made of three distinct protiens
They have side arms that help in keeping proper spacing between other intermediate filaments
Their important for detaining the diameter of the axon in the nerve cell which can help to create the particular speed of the action potential
What is something with neurofilment s that causes diseases
The aggregation of the neurofilmants causes Alzheimer’s and Parkinson’s
What are the major function of intermediate filaments
Structural support
Spatial organization
