Normal cellular function depends on the cytoskeleton—an array of filamentous structures that gives cells their shape and forms the tracks that motor proteins use to transport cargo within the cell. In addition to moving along microtubules, a group of motor proteins called kinesin-8s also act to remodel the cytoskeleton by depolymerizing microtubules. How kinesin-8s combine these two distinct activities—motility and microtubule depolymerization—has not been clear.

In research published online on July 20 in Nature Communications, Hernando Sosa, Ph.D., and colleagues used cryo-electron microscopy, X-ray crystallography and biochemistry assays  to solve the structures of different forms of a kinesin-8 attached to microtubules and microtubule-depolymerization intermediates. Their findings reveal how this unique kinesin is adapted to both walk along and depolymerize microtubules.

The structures solved by Dr. Sosa and his team may lead to drugs that bind these proteins. The study’s kinesin-8 motor proteins were derived from Candida albicans—the cause of the yeast infection candidiasis, which can be life-threatening in immunocompromised people. Solving the structures of these proteins could lead to anti-candidiasis drugs that work by targeting kinesin-8 proteins.

Dr. Sosa is professor of biochemistry at Einstein.