Biosingularity

Researchers discover cell’s ‘quality control’ mechanism

Posted on: August 10, 2008

Discovery may lead to new treatments for cystic fibrosis, other inherited diseases

Researchers in Japan and Canada have discovered a key component of the quality control mechanism that operates inside human cells – sometimes too well. The breakthrough has significant implications for the development of new treatments for cystic fibrosis (CF) and some other hereditary diseases, the researchers say. Their results were published July 25 in the journal Science.

Dr. Kazahiro Nagata and colleagues at Kyoto University and the Japan Science Technology Agency, and Dr. David Thomas and Dr. Gregor Jansen at McGill University in Montreal, have discovered the important role played by an enzyme called ERdj5 inside the cell’s endoplasmic reticulum (ER). The ER acts as a sort of packaging plant that folds and prepares proteins for distribution inside or outside the cell. But when proteins are misfolded in the ER, they must be destroyed in a degradation process – and that is where ERdj5 comes into play.

“ERdj5 is like a quality control inspector,” explained Dr. Thomas, McGill’s Chair of Biochemistry and Canada Research Chair in Molecular Genetics. “If you ever owned an AMC Pacer and you now drive a BMW, you know the difference quality control can make. That’s what ERdj5 does, it recognizes when a protein has ‘manufacturing defects’ and degrades it before it can be distributed.”

The ERdj5 enzyme is the first protein found to be capable of breaking the disulfide bonds that hold the misfolded proteins together in the ER. Once those bonds are broken, the researchers say ERdj5 also helps other enzymes and molecules break down the misfolded proteins completely so that the constituent amino acids can be recycled for further protein synthesis.

“Unfortunately, the mechanism sometimes works a little too well,” Dr. Thomas said. “It insists on BMW quality when a Honda would do. For example, some people carry a mutated version of the protein CFTR. The mutated protein is damaged but would still work fine if it were distributed, but in some individuals, the quality control mechanism insists on degrading it. It’s the degradation of the protein, not the mutation itself, which causes cystic fibrosis. We’re hoping this discovery will open up new avenues of research into treatments for CF.”

Source: McGill University
With contributions courtesy of Science Magazine.

About these ads

1 Response to "Researchers discover cell’s ‘quality control’ mechanism"

What about the ubiquitin-proteasome pathway, which tags molecules for destruction and later disposal? It also contributes to the QC.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Enter your email address to subscribe to this blog and receive notifications of new posts by email.

Join 936 other followers

Follow me on Twitter

Medical Professional Database Award

 Doctor

Visitors Now

who's online

Blog Stats

  • 1,406,831 hits

Categories

Top Rated

Flickr Photos

Inzell 2014

Fullerton Station at night, Chicago

Color Contest

black`n white pearls

St. Peter's

Jack of speed

Good Fence, Good Neighbor

Good morning, world!

Bella Coola BC.

Early Morning Light

More Photos

Maps

Networked blogs

Follow

Get every new post delivered to your Inbox.

Join 936 other followers

%d bloggers like this: