Intermediate Filaments Flashcards
What is the intermediate filament diameter?
8-10nm
What is the most stable and least soluable component of the cytoskeleton?
Intermediate filaments
Intermediate filaments dont contain n____ b____ s_____
Nucleotide Binding Site
What is suggested about the IF structure?
Primary structural function
Maybe a trimer with regions of heliex and non heliex
What two things is there no evidence for in intermediate filaments?
Cellular pool of non polymerised subunits
dynamic equilibrium between polymerised and soluble forms
How is the number and length of IF controlled?
Proteolytic enzymes are ablet o degrade classes of IF
Why are IFs variable whereas MT and MF are conserved?
May come from different accessory proteins
How is directionality of movement achieved?
MT and MF have polarity without this motor proteins would move randomly.
Describe some characteristics of motor proteins
Power Stroke
Recovery Stroke
Globular head region moves filaments along
Tail- point of attraction of the motor protein and its cargo
Define Power stroke
ATP hydrolysis causes a conformational change thrusting the head backwards creating tension in the tail. This moves the tail and cargo forwad
Define recovery stroke
Occurs when the protein is lossly attached to the filaments
The head moves along by thermal motion / diffusion
What are the 3 domains of the Kinesin?
1) large globular head binds microtubules and ATP
2) stalk
3) small globular head binds to vesicle
How many families of Kinesin have been found?
12
What is myosins function on actin filaments?
Acts as a motor protein
What is the role of
Myosin V
Myosin XI
Myosin V- vesicle and organelle transport
Myosin XI - cytoplasmic streaming
What two things does migration/movement of the cells require?
Anchorage
Active cytoskeleton
Does the organisation of Actin fibres vary significantly in different areas of the cell?
Yes
How many types of protein is the cilium built from?
Over 200 specific types
Describe the structure of the cilia.
How many tubules with how many protofilaments?
A tubules has 13 profilaments
B tubues has 10
Cental pair has 13 profilaments
What is the primary driving force for the movement of the cilary dynein?
What does this movement cause?
How long did each cilium?
ATP-driven
Movement causes MT in cilium care to slide against each other which causes the cilium to bend
What can a lack of Dystrophin cause?
disease
