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: 'Office life' of bacteria may be their weak spot

add to favorites email to friend print save as pdf

Related Stories

Astronomers pinpoint 'Venus Zone' around stars

2 hours ago

San Francisco State University astronomer Stephen Kane and a team of researchers presented today the definition of a "Venus Zone," the area around a star in which a planet is likely to exhibit the unlivable ...

History books becoming next fight in Texas schools

3 hours ago

The next ideological fight over new textbooks for Texas classrooms intensified Wednesday with critics lambasting history lessons that they say exaggerate the influence of Moses in American democracy and negatively portray ...

Amazon deforestation up 29 pc in 2013

4 hours ago

Deforestation in the Amazon rose 29 percent between August 2012 and July of last year to 5,891 square kilometers (2,275 square miles), Brazilian officials said Wednesday, posting an amended figure.

Recommended for you

Transparent larvae hide opaque eyes behind reflections

3 hours ago

Becoming invisible is probably the ultimate form of camouflage: you don't just blend in, the background shows through you. And this strategy is not as uncommon as you might think. Kathryn Feller, from the University of Maryland ...

Peacock's train is not such a drag

4 hours ago

The magnificent plumage of the peacock may not be quite the sacrifice to love that it appears to be, University of Leeds researchers have discovered.

Iberian pig genome remains unchanged after five centuries

10 hours ago

A team of Spanish researchers have obtained the first partial genome sequence of an ancient pig. Extracted from a sixteenth century pig found at the site of the Montsoriu Castle in Girona, the data obtained indicates that ...

User comments : 0