Nixing immaturity in red blood cells

May 04, 2008

A process of self-digestion called autophagy prompts the maturation of red blood cells. Without a protein called Nix, the cells would not effectively rid themselves of organelles called mitochondria and consequently become short-lived, leading to anemia, said researchers at Baylor College of Medicine in Houston in a report that appears online today in the journal Nature.

“It’s changed our thinking on autophagy,” said Dr. Jin Wang, assistant professor of immunology at BCM and senior author of the report. During autophagy, the cell forms an envelope or vesicle around components of the cell that need to be degraded and removed. The vesicle then fuses with a cellular component called a lysosome that degrades its contents. The inclusion of components in the cell by autophagy vesicles was generally considered to be nonspecific.

“This is not a random process,” said Wang. “Nix is instructing the cell to get rid of these mitochondria.”

Nix accomplishes this task by disrupting the mitochondrial membrane potential (represented by difference in voltage across the inner membrane of the mitochondria. The interior is negative and the outside positive. The difference generates a force that drives the synthesis of ATP, the cell’s energy molecule).

“We think the finding is not limited to the clearance of mitochondria in red blood cells,” said Wang. “When other cells get old or stressed, their organelles may become damaged and need to be cleared by autophagy for quality control. If the cells lack such quality controls, they might have problems that result in aging, cancer and neurodegenerative diseases.”

“It helps get rid of old or damaged mitochondria,” he said. “It is a way to keep the cell functioning without going through programmed cell death (apoptosis).”

“Such specific regulation of autophagy may also be important for cell types in the muscle, brain and pancreas,” said Dr. Min Chen, assistant professor of immunology at BCM and a corresponding author of this work. “The next step is to identify proteins interacting with Nix for mitochondrial quality control by autophagy”. Other factors may also regulate this process in addition to Nix, said Hector Sandoval, a BCM graduate student who is the first author of this paper.

Source: Baylor College of Medicine

Explore further: Team identifies gene responsible for some cases of male infertility

Related Stories

New degradation proteins show route to cell survival

Jun 04, 2015

Studies by researchers at Tokyo Institute of Technology and colleagues reveal two proteins that induce degradation of certain cell constituents to help cell survival under nutrient-limiting conditions.

Protein 'comet tails' propel cell recycling process

Jun 18, 2015

Several well-known neurodegenerative diseases, such as Lou Gehrig's (ALS), Parkinson's, Alzheimer's, and Huntington's disease, all result in part from a defect in autophagy - one way a cell removes and recycles ...

Lace plants explain programmed cell death

Jul 24, 2012

Programmed cell death (PCD) is a highly regulated process that occurs in all animals and plants as part of normal development and in response to the environment. New research published in BioMed Central's open access journal ...

Cells target giant protein crystals for degradation

Mar 12, 2015

Researchers at the RIKEN Brain Science Institute in Japan engineered a fluorescent protein that rapidly assembles into large crystals inside living cells, and showed that cells actively targeted the crystals ...

Recommended for you

A high-fat diet may alleviate mitochondrial disease

22 hours ago

Mice that have a genetic version of mitochondrial disease can easily be mistaken for much older animals by the time they are nine months old: they have thinning grey hair, osteoporosis, poor hearing, infertility, ...

Cheek muscles hold up better than leg muscles in space

22 hours ago

It is well known that muscles need resistance (gravity) to maintain optimal health, and when they do not have this resistance, they deteriorate. A new report published in the July 2015 issue of The FASEB Journal, however, sugges ...

Sialic acid: A key to unlocking brain disorders

Jun 30, 2015

A new report published in the July 2015 issue of The FASEB Journal suggests that a common molecule found in higher animals, including humans, affects brain structure. This molecule may play a significant role in how brain ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.