Speed & Direction of Myosins

Speed & Direction of the Myosins

Page updated 12/3/03

Members of the myosin super-family vary enormously in their capacity to move relative to microfilaments both in the speed and even in the direction travelled. Methods to determine both have been developed and these are outlined below.

The Nitella motility assay.

Myosin	Species/source	Speed	Direction	Step size	Force (pN)	Reference (in order)
Myosin I
Myosin II


Myosin III	Striped bass	?	?	?	?	Dose et al, 2003;
Myosin IV
Myosin V				35 nm		Ali et al, 2002;
Myosin VI
Myosin VII
Myosin VIII
Myosin IX
Myosin X
Myosin XI	Nicotiana	7mM/sec	Plus	35 nm	0.5	Tominaga et al, 2003;
Myosin XII





References:- Ali, M. Y., Uemura, S., Adachi, K., Itoh, H., Kinosita jr, K. & Ishiwata, S. (2002) Myosin V is a left handed spiral motor on the right-handed actin helix. Nature Struct. Biol. 9, 464-467. Dose, A. C., Hillman, D. W., Wong, C., Sohlberg, L., Lin-Jones, J. & Burnside, B. (2003) Myo3A, One of Two Class III Myosin Genes Expressed in Vertebrate Retina, Is Localized to the Calycal Processes of Rod and Cone Photoreceptors and Is Expressed in the Sacculus, Mol. Biol. Cell. 14, 1058-1073. Tominaga, M., Kojima, H., Yokota, E., Orii, H., Nakamori, R., Katayama, E., Anson, M., Shimmen, T. & Oiwa, K. (2003) Higher plant myosin XI moves processively on actin with 35 nm steps at high velocity. EMBO J. 22, 1263-1272.