Motor proteins Side notes: Motor proteins Bind to a polarized cytoskeletal filament Move along the filament Use energy from the ATP hydrolysis There are dozens of different motor proteins Structure of a motor protein Head region (motor domain, which binds to a filament and hydrolyzes ATP) Tail region (binds to the cargo) Which type of cytoskeletal filaments is not associated with motor protein movements? 1. 2. 3. Microtubules Intermediate filaments Actin Functions of motor proteins Can carry cargo: Membrane - enclosed organelles Golgi stacks Secretory vesicles RNA Cause cytoskeletal filaments to slide against each other Muscle contractions, ciliary beating, cell division Groups of motor proteins Moving along actin filaments: Myosin's (mostly move to + ends, some to - ends) Moving along microtubules: Kinesins (mostly move to + end) Dyneins (move to - end)