Cytoskeleton Flashcards
Properties required of a cytoskeleton
- Determine shape and form (Must be able to resist being pulled apart or ruptured, and maintain their orientation)
- Have capacity for remodelling
- Reliability
What are the 3 major cytoskeleton systems?
- Actin Filaments (aka microfilaments)
- Intermediate Filaments
- Microtubules
Reorganisation of cytoskeleton filaments to a new site:
Cytoskeleton filaments are composed of small soluble subunits that can reversibly form large polymers:
In response to a signal (e.g. cytokines, growth factor), the filaments will disassemble and rapidly diffuse to the new site, where they are then reassembled.
Effects of mechanical stress on protofilaments:
Single protofilaments are prone to mechanical stress (Due to only single bonds) - Makes them thermally unstable.
Multiple protofilaments are resistant to mechanical stress (Due to multiple bonds) - Makes them thermally stable.
Why is a dynamic cytoskeleton required? How dynamic are each of the cytoskeleton filaments, and what is responsible for remodelling them?
It allows for rapid changes in cell shape that are required for cell motility.
Actin Filaments - Very dynamic, remodelled by ATP.
Intermediate Filaments - Rather stable, remodelled by phosphorylation.
Microtubules - Extremely dynamic, remodelled by GTP.
The Cytoskeleton is required for cell polarity.
TRUE OR FALSE
TRUE
The apical and baso-lateral membranes are functionally different.
e.g. Brush border/the microvillus tips apical surface is suited to increase surface area for absorption, distinctly different from the basolateral surfaces of the cell.
BLANKS transport vesicles along actin filaments and microtubules.
Molecular motors (e.g. Kinesin, Dynein)
What are some cytoskeleton molecules that are involved in cancer?
Adhesion molecules, such as “cadherins”.
Signalling molecules such as “ras”.
