Dartmouth researchers find new protein function

Jan 09, 2009
Protein NOD at the end of a microtubule (illustration by Jared Cochran)

A group of Dartmouth researchers has found a new function for one of the proteins involved with chromosome segregation during cell division. Their finding adds to the growing knowledge about the fundamental workings of cells, and contributes to understanding how cell function can go wrong, as it does with cancerous cells.

The researchers studied a protein called NOD, distantly related to the motor proteins that power diverse cellular activities, including intracellular transport, signaling, and cell division. They used X-ray crystallography to determine its structure, and then they used enzyme kinetics to find out how it performed. While this protein is found in fruit flies, the results are helpful in determining how related proteins work in humans.

"This study on NOD provided evidence for a new way a kinesin motor could function," said Jared Cochran, a postdoctoral fellow at Dartmouth and the lead author on the study. "Rather than moving on its own, it hitches a ride on the ends of microtubules which results in a dynamic cross-linking between the arms of chromosomes and the cell's growing spindle of microtubules. If NOD doesn't function properly, then the two cells end up with either both or none of that particular chromosome, which is lethal [to the cell and the organism] in most cases."

With colleagues from Lawrence Berkeley National Laboratory, Stowers Institute for Medical Research in Kansas City, Missouri, and Kansas University Medical Center in Kansas City, Kansas, the Dartmouth group published their study in the Jan. 9, 2009, issue of the journal Cell. Their paper is titled, "ATPase Cycle of the Nonmotile Kinesin NOD Allows Microtubule End Tracking and Drives Chromosome Movement."

"Before this study, it had been shown that kinesin motors either walked along their microtubule tracks or functioned to break microtubules apart," says Jon Kull, the senior author on the paper, associate professor of chemistry at Dartmouth, and a 1988 Dartmouth graduate. "This work describes a novel mode for kinesin function, in which NOD does not walk, but rather alternates between grabbing on to and letting go of the end of the growing filament, thereby tracking the end as it grows. The diversity of function of these proteins is remarkable."

One of the authors on the paper, Natasha Mulko, is a 2007 Dartmouth graduate, and worked on this project as her senior honors thesis in chemistry. Mulko is currently a graduate student in dentistry at Creighton University. "Natasha's work was integral to this study as she worked on obtaining and improving the protein crystals necessary to solve the structure," says Kull, her thesis advisor.

Source: Dartmouth College

Explore further: GMO mosquito plan sparks outcry in Florida

add to favorites email to friend print save as pdf

Related Stories

What causes motor complications of Parkinson's treatment?

Jan 29, 2009

People with Parkinson's disease commonly suffer a slowing or freezing of movement caused by the death of neurons that make dopamine, a key chemical that allows brain cells to send and receive messages essential ...

Recommended for you

GMO mosquito plan sparks outcry in Florida

21 hours ago

A British company's plan to unleash hordes of genetically modified mosquitoes in Florida to reduce the threat of dengue fever and other diseases has sparked an outcry from fearful residents.

Population genomics unveil seahorse domain

Jan 30, 2015

In a finding vital to effective species management, a team including City College of New York biologists has determined that the lined seahorse (Hippocampus erectus) is more a permanent resident of the we ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.