Featured Research

from universities, journals, and other organizations

New Model For Nuclear Pore Complex Backed By Structural Study

Date:
January 3, 2009
Source:
Rockefeller University
Summary:
In higher organisms, the genetic material is confined and protected in the cell nucleus. In order for a healthy cell to function, the DNA must send manufacturing orders through the double membrane of the nucleus and into the cell's cytoplasm, where the protein production factories are and where most cellular functions are carried out. The sole portals through which these instructions pass -- nuclear pore complexes -- have a say in what the orders are and how they are conveyed. But these conspicuously large structures have ironically proved all but inscrutable to researchers over the years.

Core pore. A new model for the nuclear pore complex predicts that a membrane "coat" is scaffolded by two alternating pairs of upright proteins (yellow). These "fence posts" are predicted to be linked horizontally by three other yet to be discovered proteins (green).
Credit: Image courtesy of Rockefeller University

In higher organisms, the genetic material is confined and protected in the cell nucleus. In order for a healthy cell to function, the DNA must send manufacturing orders through the double membrane of the nucleus and into the cell’s cytoplasm, where the protein production factories are and where most cellular functions are carried out. The sole portals through which these instructions pass — nuclear pore complexes — have a say in what the orders are and how they are conveyed. But these conspicuously large structures have ironically proved all but inscrutable to researchers over the years.

Related Articles


“The nuclear pore complex is one of the most mysterious things in cell biology. It’s basically a black box,” says Andrι Hoelz, a research associate at The Rockefeller University who studies the complex in John D. Rockefeller Jr. Professor Gόnter Blobel’s Laboratory of Cell Biology.

But more and more light is shining in. On the cover of the December 26 issue of Molecular Cell, Hoelz, Blobel and their colleagues illuminate the atomic structure of a key protein at the heart of the complex. The finding advances a new model that the lab proposed last year. The model proposes a cylindrical nuclear pore complex comprised of rings of alternating protein structures that zip together, providing the flexibility and space the pore needs to let pass a variety of materials in and out of the cell’s nucleus. “We were very excited to find a protein that is so similar in structure to what our model predicts,” Hoelz says.

For the past few years, Hoelz and his colleagues have been chipping away at the nuclear pore complex one protein at a time. Their piecemeal approach, using x-ray crystallography to identify the atoms in each protein, is necessary because the complex is too large and pliable to succumb to traditional imaging or genetic analysis, Hoelz says. The nuclear pore complex is built from about 30 different proteins and is 30 times the size of the ribosome, the site of protein production, and 1,000 times the size of the common ion channels found in all cell membranes. So far, the Blobel lab has solved the structure of four of seven proteins thought to provide a cylindrical coat for the pore membrane. They are about to publish the molecular makeup of a fifth, Hoelz says.

The structure to be published on Friday, a pair of nucleoporin proteins called Seh1-Nup85, is similar in shape and size to the last one the lab discovered, Sec13-Nup145C. Both pairs form bent rods and are about the same length as the depth of the nuclear pore complex found in yeast. This fits with the lab’s model, which suggests that these two protein pairs alternate around the interior lining of the complex, forming a picket fence of sorts. The model predicts that the remaining three proteins of this coat will horizontally join these protein pairs together. “Clearly, more work is required to know for sure, whether or not our model is correct,” says Hoelz.

Once researchers decipher the rest of the complex’s atomic structure, they will be able to precisely manipulate different parts and study the effects, hashing out the role this key portal plays in the process of turning DNA into proteins. “I think if we figure out the whole structure, we will open up a whole new field,” Hoelz says.

Given the central role of the nuclear pore complex in the most basic cell processes, defects in its assembly, structure and function can have lethal consequences. Its proteins have been associated with primary biliary cirrhosis, cancer, viral infections and triple A syndrome, says Erik Debler, postdoctoral fellow in the Blobel laboratory and first author of the paper. A better understanding of how the complex works could lead to treatments for these diseases. The nuclear pore complex is also of basic scientific interest as a key element in a very ancient evolutionary coup that is found in every cell more complicated than the simplest single-celled microorganisms: the nucleus.

“What distinguishes us from bacteria is that we have a cell nucleus,” Hoelz says. “It protects the DNA from environmental factors. It divides and segregates functions in different parts of the cell. It introduces all kinds of complexities that lower organisms do not have. The nuclear pore complex plays a big part in all of that.”


Story Source:

The above story is based on materials provided by Rockefeller University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Debler et al. A Fence-like Coat for the Nuclear Pore Membrane. Molecular Cell, 2008; 32 (6): 815 DOI: 10.1016/j.molcel.2008.12.001

Cite This Page:

Rockefeller University. "New Model For Nuclear Pore Complex Backed By Structural Study." ScienceDaily. ScienceDaily, 3 January 2009. <www.sciencedaily.com/releases/2008/12/081227224147.htm>.
Rockefeller University. (2009, January 3). New Model For Nuclear Pore Complex Backed By Structural Study. ScienceDaily. Retrieved October 31, 2014 from www.sciencedaily.com/releases/2008/12/081227224147.htm
Rockefeller University. "New Model For Nuclear Pore Complex Backed By Structural Study." ScienceDaily. www.sciencedaily.com/releases/2008/12/081227224147.htm (accessed October 31, 2014).

Share This



More Plants & Animals News

Friday, October 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Watch Baby Goose Survive A 400-Foot Cliff Dive

Watch Baby Goose Survive A 400-Foot Cliff Dive

Buzz60 (Oct. 31, 2014) — For its nature series Life Story, the BBC profiled the barnacle goose, whose chicks must make a daredevil 400-foot cliff dive from their nests to find food. Jen Markham has the astonishing video. Video provided by Buzz60
Powered by NewsLook.com
World's Salamanders At Risk From Flesh-Eating Fungus

World's Salamanders At Risk From Flesh-Eating Fungus

Newsy (Oct. 31, 2014) — The import of salamanders around the globe is thought to be contributing to the spread of a deadly fungus. Video provided by Newsy
Powered by NewsLook.com
Alcoholic Drinks In The E.U. Could Get Calorie Labels

Alcoholic Drinks In The E.U. Could Get Calorie Labels

Newsy (Oct. 31, 2014) — A health group in the United Kingdom has called for mandatory calorie labels on alcoholic beverages in the European Union. Video provided by Newsy
Powered by NewsLook.com
Malaria Threat in Liberia as Fight Against Ebola Rages

Malaria Threat in Liberia as Fight Against Ebola Rages

AFP (Oct. 31, 2014) — Focus on treating the Ebola epidemic in Liberia means that treatment for malaria, itself a killer, is hard to come by. MSF are now undertaking the mass distribution of antimalarials in Monrovia. Duration: 00:38 Video provided by AFP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins