Earlier this year, as reported in The Journal of Cell Biology, researchers in Holzbaur's lab found that a mutation in dynactin leads to degeneration of motor neurons, the hallmark of motor neuron disease. This mutation decreases the efficiency of the dynein-dynactin motor in "taking out the trash" of the cell, and thus leads to the accumulation of misfolded proteins in the cell, which may in turn lead to the degeneration of the neuron.
Scientists are now finding that many other molecular motors are remarkably flexible in their behavior. In several further papers published in the Proceedings of the National Academy of Sciences and The EMBO Journal, Goldman and colleagues at the University of Illinois found that a "local delivery" motor, termed myosin V, moves cargo with a variable path short distances along another type of cellular track called actin. This flexibility could help myosin V navigate crowded regions of the cell where the actin filaments criss-cross and where other cellular components would otherwise pose an impediment to motion. Defects in myosin V function also result in neurological defects.
Most of these molecular motors are associated with specific diseases or developmental defects, so understanding the puzzling aspects of their behavior in detail is necessary for building nanotechnological machines that, for example, could replace defective motors. "The ultimate goal is to find ways to treat motor neuron disease as well as other diseases that involve cellular motors and also construct nano-scale machines based on these biological motors," says Goldman.