Nav: Home

Study unveils novel crosstalk mechanism between mitochondrial translation and cytoplasmic translation

April 14, 2016

Protein is the fundamental substance of life. The genetic code directing protein synthesis is stored in DNA. When a cell is instructed, the code information transfers from DNA to mRNA. Then, information on mRNA is further transferred to protein.

There are two sets of protein translation systems in mammalian cells - the cytoplasmic translation system and the mitochondrial translation system - both of which are composed of ribosome, tRNAs and translation factors. The translation system translates mRNA into biologically competent protein according to the information on mRNA. However, the coordination mechanism between the cytoplasmic translation system and the mitochondrial translation system has been a mystery.

A research article entitled "Mammalian Elongation Factor 4 Regulates Mitochondrial Translation Essential for Spermatogenesis" was published online in the journal Nature Structural & Molecular Biology on April 11, 2016. It describes the crosstalk mechanism between mitochondrial translation and cytoplasmic translation.

Mitochondrial translation elongation factor 4 (mtEF4) is a quality control factor in protein translation. Although protein is highly conserved in evolution, previous mtEF4 gene knockouts in some model organisms did not show significant phenotypic change.

In this study, by using a systemic mtEF4 gene knockout mouse model, researchers found that mtEF4 knockout damages the oxidative phosphorylation function in germ cells of male mice, thus causing male sterility.

Further study found that the rate of mitochondrial protein translation increased after mtEF4 was knocked out. However, the price was a lower "qualified rate" for protein and a shorter protein half-life. In order to keep step with the "quickened" mitochondrial translation, somatic cells activated the mTOR signaling pathway in order to accelerate cytoplasmic translation and balance mitochondrial translation. In this way, somatic cells successfully resolved the negative impact of high-speed mitochondrial translation.

In contrast, the mTOR signaling pathway could not be activated in germ line cells, because the mitochondrial complex assembly of germ cells failed to assemble, and the sperm maturation process stagnated at the round sperm stage, ultimately resulting in male sterility.

This study reveals a new information exchange mechanism within the cell (see figure below): The mTOR signaling pathway balances the dynamic between mitochondrial translation and cytoplasmic translation. When the mitochondrial translation rate increases, the mTOR signaling pathway is activated, which causes the increase in the cytoplasmic protein translation rate to counteract pressure from the increased mitochondrial translation, thus representing a new evolutionary adaptation mechanism. In addition, this study revealed a new reason for male infertility and is of great value for the clinical treatment of male infertility.

This research involved cooperation by many institutions, including the Institute of Biophysics (IBP), the Institute of Zoology, the Academy of Military Medical Sciences, the Tianjin University of Science and Technology, and other institutes. The Institute of Biophysics and the University of the Chinese Academy of Sciences are the first and the second institutions, respectively. Prof. QIN Yan (IBP) is the corresponding author. GAO Yanyan and BAI Xiufeng are the co-first authors of this paper. This work was also supported by the Chinese Ministry of Science and Technology, the National Natural Science Foundation and Key Projects of the Chinese Academy of Sciences.

Chinese Academy of Sciences Headquarters

Related Protein Articles:

Hi-res view of protein complex shows how it breaks up protein tangles
A new, high-resolution view of the structure of Hsp104 (heat shock protein 104), a natural yeast protein nanomachine with six subunits, may show news ways to dismantle harmful protein clumps in disease.
Breaking the protein-DNA bond
A new Northwestern University study finds that unbound proteins in a cell break up protein-DNA bonds as they compete for the single-binding site.
FASEB Science Research Conference: Protein Kinases and Protein Phosphorylation
This conference focuses on the biology of protein kinases and phosphorylation signaling.
Largest resource of human protein-protein interactions can help interpret genomic data
An international research team has developed the largest database of protein-to-protein interaction networks, a resource that can illuminate how numerous disease-associated genes contribute to disease development and progression.
STAT2: Much more than an antiviral protein
A protein known for guarding against viral infections leads a double life, new research shows, and can interfere with cell growth and the defense against parasites.
A protein makes the difference
It is well-established knowledge that blood vessels foster the growth of tumors.
Nuclear protein causes neuroblastoma to become more aggressive
Aggressive forms of neuroblastoma contain a specific protein in their cells' nuclei that is not found in the nuclei of more benign forms of the cancer, and the discovery, made through research from the University of Rochester Medical Center, could lead to new forms of targeted therapy.
How a protein could become the next big sweetener
High-fructose corn syrup and sugar are on the outs with calorie-wary consumers.
High animal protein intake associated with higher, plant protein with lower mortality rate
The largest study to examine the effects of different sources of dietary protein found that a high intake of proteins from animal sources -- particularly processed and unprocessed red meats -- was associated with a higher mortality rate, while a high intake of protein from plant sources was associated with a lower risk of death.
Protein in, ammonia out
A recent study has compiled and analyzed data from 25 previous studies.

Related Protein Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...