Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Clues point to cause of a rare fat-distribution disease

Novel modification of structural protein implicated

Studying a protein that gives structure to the nucleus of cells, Johns Hopkins researchers stumbled upon mutations associated with familial partial lipodystrophy (FPLD), a rare disease that disrupts normal patterns of fat distribution throughout the body.

"Our findings open new paths for learning how and why fat cells are disproportionately affected by mutations in the protein lamin A, which is found in the nucleus of most cells of the body," says Katherine Wilson, Ph.D., professor of cell biology at the Johns Hopkins University School of Medicine.

According to the researchers, this is the first report that another protein, SUMO1, can attach to lamin A. Importantly, they found that FPLD-causing mutations in lamin A prevent this attachment. Details of the study were published in the Feb. 1 issue of the journal Molecular Biology of the Cell.

Wilson says lamin A is primarily known for giving shape to the nucleus. "It forms networks of strong 'cables' at the nuclear membrane and works with other proteins to create and maintain the three-dimensional environment in which chromosomes are properly organized, protected and expressed," she says.

When the Wilson group made their discovery, they were studying lamin A binding to another protein, actin. Actin can sometimes form a complex with certain SUMO proteins, small proteins often attached to other proteins to alter their functions, their locations and their interactions with additional proteins.

"Sometimes you go into an experiment looking for one thing but you find another," says Wilson. "We wanted to know if lamin A could bind to actin-SUMO1 complexes. Instead, we found that SUMO1 itself attaches to lamin A."

SUMO1 is usually attached to proteins at sites with certain properties; these sites can be predicted by the surrounding amino acids, the basic building blocks of proteins whose blueprints are found in genes. So the researchers searched lamin A's amino acid sequence for predicted binding sites and found five. Using targeted genetic techniques, they created lamin A variants, each with a mutation at a different predicted SUMO1 attachment site. They then added SUMO1 to the mutants and tested whether it could attach to them or not.

Two mutations significantly decreased SUMO1 attachment. One was at a predicted site; the other was unexpectedly in their comparison "control" variant. "Since the mutation site in our control variant was not a predicted SUMO1 attachment site, we were curious about it," explains Wilson. "Mutations in lamin A cause more than 15 different diseases, so we checked the genetic database to see if any diseases were associated with mutations near the SUMO1 attachment site, and FPLD leapt out like a neon sign."

FPLD is a very rare condition that starts around puberty. Fat on the legs of patients is reduced while it accumulates at other locations, including the neck and face. Patients can also become diabetic.

Twenty-four different mutations in lamin A can cause FPLD. To see if two other FPLD-causing mutations near the SUMO1 attachment site affected SUMO1 attachment, the team created these variants and tested them as before. One of the new variants did show decreased SUMO1 attachment. Based on the location of that mutation and one of the other SUMO1-disrupting mutations, the researchers were able to identify a "patch" on the surface of the lamin A protein that is important for SUMO1 attachment.

Exactly how lamin A and SUMO1 connect to FPLD is still a mystery. "We can only speculate on how lamin A and SUMO1 work together to regulate fat cells," says Wilson. "But these results raise new research questions that will hopefully move FPLD studies forward."

Other authors of the report include Dan Simon of the Johns Hopkins University School of Medicine and Tera Domaradzki and Wilma Hofmann of the University at Buffalo, The State University of New York.

This work was supported by grants from the National Institute of General Medical Sciences (RO1 GM048646) and the Department of Defense CDMRP (PC111523).

On the Web:

Link to article:

Wilson Lab:

Related stories:

Promising Pursuits: Name That Field (the final story of the article)

Media Relations and Public Affairs
Media Contacts: Catherine Kolf; 443-287-2251;
Vanessa McMains; 410-502-9410;
Shawna Williams; 410-955-8236;

Catherine Kolf | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht International team discovers novel Alzheimer's disease risk gene among Icelanders
24.10.2016 | Baylor College of Medicine

nachricht New bacteria groups, and stunning diversity, discovered underground
24.10.2016 | DOE/Lawrence Berkeley National Laboratory

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

Im Focus: Ultra-thin ferroelectric material for next-generation electronics

'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.

Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

New method increases energy density in lithium batteries

24.10.2016 | Power and Electrical Engineering

International team discovers novel Alzheimer's disease risk gene among Icelanders

24.10.2016 | Life Sciences

New bacteria groups, and stunning diversity, discovered underground

24.10.2016 | Life Sciences

More VideoLinks >>>