Chapter 14:Cell Motility

Microtubules provide a set of tracks for transport of a variety of organelles and vesicles

True

Inbound traffic

Traffic towards the plus end

Outbound Traffic

Traffic towards the minus end

MT-associated motor proteins

Kinesins and dyneins walk along the microtubules and provide the force needed for movement

Fast axonal transport

Proteins produced in the cell body are transported to the nerve ending at rates of about 2um/sec

Fast axonal transport involves

Packaging of these proteins into vesicles for transpor

Kinesin

Involved in ATP-dependent transport toward the plus end

Kinesin consists of

2 dimerized heavy chains and light chains

Heavy chains

Contain globular domains that attach to microtubules, a coiled coil stalk, a lever-like neck that connects the 2 chains and a tail

Light chains

Are associated with the tail

Cell motility involves

movement of a cell or organism through the environment, movment of components in the cell, and contractility

Contractility

The shortening of muscle cells, a specialized form of motility

Intracellular movement

Microtubules play a role in the separation of chromosomes during cell division

To generate movement microtubules and microfilaments provide a scaffold for motor proteins that produce motion at the molecular level

True

Microtubules and Microfilaments

The roads

Motor proteins

The cars

Microtubule-Based-Motility

Fast axonal transport in neurons; the sliding of microtubules in cillia and flagella

Microfilament-Based-Motility

Muscle contraction

Common features of molecular motors(1)

Couple atp hydrolysis to changes in shape and addition of the motor protein

Common features of molecular motors(2)

Undergo cycles of ATP hydrolysis, ADP release, and acquisition of new ATP

Common features of molecular motors(3)

Move along a cytoskeletal filament for long distances