Skip to main content

Nuclear pore complex outer rings: No longer 'one size fits all'

In eukaryotic cells, the nucleus is walled off from the rest of the cell by the nuclear envelope. All transport into and out of the nucleus occurs via cylindrical channels called nuclear pore complexes (NPCs) that penetrate the nuclear envelope. Each NPC is made up of eight repeating protein complexes containing at least 30 different types of proteins, called nucleoporins (Nups). These complexes fit together like the wedges of an orange, leaving a channel in the middle through which proteins, RNA, and signaling molecules can be transported.
The Nups at either end of the NPC form ring-like structures that frame the openings of the channel. So far, all work in eukaryotic cells has suggested that these outer rings are identical, comprising equal numbers of nine or ten different Nups linked together in repeating Y-shaped structures.
But in a study published this week in PLoS Genetics, a team lead by researchers from Osaka University and National Institute of Information and Communications Technology (NICT) found that the "one size fits all" theory may not hold true.
"We wanted to take a closer look at the NPCs of fission yeast, Schizosaccharomyces pombe," says lead author of the study Haruhiko Asakawa at Osaka University. "Like other eukaryotes, S. pombe has a conserved set of Nups, but unlike these other species, the outer ring structures are made up of unequal numbers of the different types of proteins."
And while the researchers were expecting some differences, they weren't quite prepared for the completely divergent structures revealed by using high-powered immunoelectron and fluorescence microscopes. By carefully tracking the locations of the different proteins, they made their startling discovery.
"It's like S. pombe has completely thrown the rule book out the window," laughs senior author Tokuko Haraguchi at NICT. "We found that the proteins that make up the outer ring structures were arranged asymmetrically. Rather than having identical structures, the nuclear outer ring comprised only two types of Nups, with the seven remaining Nups all part of the cytoplasmic outer ring structure."
Interestingly, the researchers found that the asymmetrical ring structure was essential for normal cell growth in S. pombe.
"This diversity in the outer ring structures may provide clues as to how the nuclear pore is formed, along with insights into the structure and function of the cell nucleus from an evolutionary point of view," says Asakawa. "We also hope that our findings will help us to better understand the mechanisms of diseases caused by abnormal nuclear pore proteins, which in turn may lead to new treatment strategies."
Story Source:
Materials provided by Osaka University.
Note: Content may be edited.

Comments

Post a Comment

Popular posts from this blog

Dark matter may be older than the Big Bang

Dark matter, which researchers believe make up about 80% of the universe's mass, is one of the most elusive mysteries in modern physics. What exactly it is and how it came to be is a mystery, but a new Johns Hopkins University study now suggests that dark matter may have existed before the Big Bang. The study, published August 7 in  Physical Review Letters , presents a new idea of how dark matter was born and how to identify it with astronomical observations. "The study revealed a new connection between particle physics and astronomy. If dark matter consists of new particles that were born before the Big Bang, they affect the way galaxies are distributed in the sky in a unique way. This connection may be used to reveal their identity and make conclusions about the times before the Big Bang too," says Tommi Tenkanen, a postdoctoral fellow in Physics and Astronomy at the Johns Hopkins University and the study's author. While not much is known about its origins,...
Post a Comment
Read more

Home births as safe as hospital births: International study suggests

A large international study led by McMaster University shows that low risk pregnant women who intend to give birth at home have no increased chance of the baby's perinatal or neonatal death compared to other low risk women who intend to give birth in a hospital. The results have been published by  The Lancet 's  EClinicalMedicine  journal. "More women in well-resourced countries are choosing birth at home, but concerns have persisted about their safety," said Eileen Hutton, professor emeritus of obstetrics and gynecology at McMaster, founding director of the McMaster Midwifery Research Centre and first author of the paper. "This research clearly demonstrates the risk is no different when the birth is intended to be at home or in hospital." The study examined the safety of place of birth by reporting on the risk of death at the time of birth or within the first four weeks, and found no clinically important or statistically different risk between home...
Post a Comment
Read more

GSAT-11 satellite to be launched from French Guiana on Dec 5th

GSAT-11 satellite to be launched from French Guiana on Dec 5th GSAT-11 would be located at 74 East and is the fore-runner in a series of advanced communications satellite with multi-spot beam antenna coverage over Indian mainland and Islands, ISRO said. GSAT-11 is the next generation “high throughput” communication satellite configured around ISRO’s I-6K Bus. (PTI/Representational). Indian space agency ISRO is scheduled to launch GSAT-11, the “heaviest” satellite built by it, on-board Ariane-5 rocket of Arianespace from French Guiana on December 5. Weighing about 5,854 kg, GSAT-11 would play a vital role in providing broadband services across the country, and also provide a platform to demonstrate new generation applications, the Indian Space Research Organisation (ISRO) said. It is the “heaviest” satellite built by ISRO, the space agency said. GSAT-11 is the next generation “high throughput” communication satellite configured around ISRO’s  I-6K Bus, and it...
Post a Comment
Read more