Features | Partner Sites | Information | LinkXpress
Sign In
PURITAN MEDICAL
Demo Company
GLOBETECH PUBLISHING LLC

Molecular Interactions Identified That Block Protein Transfer into Mitochondria of Huntington's Disease Neurons

By BiotechDaily International staff writers
Posted on 08 Jul 2014
Image: A microscope image of a neuron with inclusion (stained orange) caused by Huntington\'s disease (Photo courtesy of Wikimedia Commons).
Image: A microscope image of a neuron with inclusion (stained orange) caused by Huntington\'s disease (Photo courtesy of Wikimedia Commons).
Researchers have identified a protein complex that interacts with the mutated form of huntingtin protein to impair transport of proteins into the mitochondria of brain cells, which leads to their malfunction and the loss of neurons that characterizes Huntington's disease.

Huntington’s disease is caused by a dominant gene that encodes a protein known as huntingtin (Htt). The 5' end of the Huntington's disease gene has a sequence of three DNA bases, cytosine-adenine-guanine (CAG), coding for the amino acid glutamine, that is repeated multiple times. Normal persons have a CAG repeat count of between 7 and 35 repeats, while the mutated form of the gene has anywhere from 36 to 180 repeats. The mutant form of Htt is broken down into toxic peptides, which contribute to the pathology of the syndrome.

Investigators at the Washington University School of Medicine (St. Louis, MO, USA) and their colleagues at the University of Pittsburgh (PA, USA) worked with in vitro culture models and with a mouse model that mimicked the early stages of Huntington's disease.

They reported in the May 18, 2014, online edition of the journal Nature Neuroscience that recombinant mutant Htt directly inhibited mitochondrial protein import in their culture model. Furthermore, mitochondria from the brain synaptosomes of presymptomatic Huntington's disease model mice and from mutant Htt-expressing primary neurons exhibited a protein import defect, suggesting that deficient protein import was an early event in Huntington's disease.

At the molecular level, the investigators spotted interactions between mutant Htt and the TIM23 (translocase of inner mitochondrial membrane 23) mitochondrial protein import complex. Overexpression of TIM23 complex subunits attenuated the mutant Htt–induced mitochondrial import defect and subsequent neuronal death, which demonstrated that deficient mitochondrial protein import caused mutant Htt-induced neuronal death.

“We showed the problem could be fixed by making cells overproduce the proteins that make this transfer possible,” said first author Dr. Hiroko Yano, assistant professor of neurological surgery, neurology, and genetics at the Washington University School of Medicine. “We do not know if this will work in humans, but it is exciting to have a solid new lead on how this condition kills brain cells.”

Related Links:

Washington University School of Medicine
University of Pittsburgh 



Channels

Drug Discovery

view channel
Image: Cancer cells were treated with a control (left) and the overstimulating compound MCB-613 (right) (Photo courtesy of Dr. Lei Wang, Baylor University College of Medicine).

Drug Candidate Propels Cancer Cells into Fatal Overdrive

A candidate drug that destroys cancer cells by stimulating them to produce more proteins than the cells can actually process was shown to kill a wide variety of cancer cells in culture and to inhibit tumor... Read more

Lab Technologies

view channel
Image: The Synergy Neo2 Multi-Mode Reader recently received Cisbio HTRF certification (Photo courtesy of BioTek Instruments Inc.).

High-Speed Multimode Microplate Reader Receives Homogenous Time-Resolved Fluorescence Certification

A new high-performance, high-speed microplate reader has received HTRF (homogenous time-resolved fluorescence) accreditation that certifies that it complies with standards for detection set by a major... Read more

Business

view channel

Innovative Microbial Diagnostics Developer Acquired by Biomedical Giant

A biotech company noted for its development of innovative products in the field of molecular microbiology diagnostics has been acquired by one of the world's largest biomedical corporations. GeneWEAVE BioSciences, Inc.(Los Gatos, CA, USA) and Roche (Basel, Switzerland) have announced that Roche will be purchasing the... Read more
 
Copyright © 2000-2015 Globetech Media. All rights reserved.