Myosin Types and Functions

What are myosins?

are motor proteins that move along actin filaments using ATP energy.

What do all myosins have in common?

They have a head (binds actin and ATP), a neck (lever arm), and a tail (binds cargo or other proteins).

What does Myosin II do?

forms thick filaments and drives muscle contraction by sliding actin filaments past each other.

Where is Myosin II found?

In muscle cells and some non-muscle cells for cell movement and cytokinesis.

What does Myosin I do?

links actin filaments to the plasma membrane and helps with membrane movement like endocytosis.

What does Myosin V do?

transports vesicles and organelles along actin filaments.

What type of motion do myosins generate?

Most move toward the plus end of actin filaments (except Myosin VI, which moves toward the minus end).