Lecture 11: Microtubule motor proteins Flashcards
What direction does kinesin move in?
Towards the plus end
What direction does dynein move in?
Towards the minus end
What is the main process of a microtubule motor protein moving?
- ATP hydrolysis loosens the attachment of head 1 to the microtubule
- ADP release and ATP binding changes the conformation of head 2
- This moves head 1 forwards
What are the two types of dynein?
Axonemal
Cytoplasmic
What is cytoplasmic dynein?
Works with its partner complex dynactin
Moves cargos by binding to adaptor proteins
What are the two roles of microtubule motors?
Facilitates membrane traffic by delivering vesicles
Position organelles into the cytoplasm
How do microtubules and motor proteins position organelles in the cytoplasm?
Cytoplasmic dynein moves the ER inwards slightly
Transports golgi apparatus towards the cell centre
What are the two types of sliding caused by motors?
Antiparallel sliding
Parallel sliding
What is antiparallel sliding?
Occurs in meiotic and mitotic spindles
What is parallel sliding?
Occurs in cilia and flagella
What are some examples of cells with flagella?
Vertebrate sperm
Protozoa
What are some examples of cells with cilia?
Protozoa
Epithelia
What are axonemes?
Specialised stable microtubule structures
Found in cilia and flagella
What is the role of axonemal dynein?
The dynein in axonemes
Drives ciliary and flagellar beating
What are myosins?
Actin based motor proteins