Soldati and Foth became interested in myosins after they discovered that the molecular motors enabled toxoplasmosis and malaria parasites to force their way into human cells.
The researchers say that although their research is theoretical and a long way from clinical applications, the new classification system will help other researchers address important biomedical puzzles more precisely.
"We hope our work will help scientists ask the right questions and perform the right kind of experiments on myosins," Foth said. "In the long term, that could lead to new drug targets being discovered more quickly."
Molecular motors run on tracks, like trains, using chemical reactions that involve the chemical compound adenosine triphosphate (ATP) for fuel. Myosin runs on the filaments of actin, a protein found in muscle cells, but kinesins and dyneins use microtubules, which are hollow protein structures inside the cell, as their track.
Movement is created several ways. Biological cargo is transported within cells by single motors that run backward and forward, the way a person moves hand over hand along a rope. Making muscles contract involves a large number of motors that work very fast in neatly arranged teams, quickly letting go of the track once they have completed their "power stroke."
Most molecular motors have a head, a neck (which powers movement), and a tail. Myosins usually look like two-headed snakes, kinesins like hairpins with a head at each end, and dyneins like three-headed flowers with one stem. Soldati and Foth have confirmed that the motor neck and tail evolved together. That finding helped them define some of their new categories.
Organisms employ all three types of motors at the same time, but in different proportions. For example, yeast uses six kinesins, five myosins, and
Source:Howard Hughes Medical Institute