Nav: Home

Molecular inhibition gets cells on the move

November 08, 2018

Osaka, Japan - To respond to changes in their environment, individual cells, including some of those that compose complex organisms, need to move. This can be accomplished by propelling themselves using projections called pseudopodia. Although this system is present within many different species, the mechanisms that control it and enable cells to move in a particular direction have not been completely clarified.

In recent work published in the journal Nature Communications, researchers at Osaka University have revealed how cells in an organism known as a slime mold establish the polarized distribution of two molecules in their outer membranes. The localization of these two molecules exclusively at different ends of a cell leads to the assembly of machinery for pseudopodium formation only at one cell end. This ensures a unidirectional force from pseudopodia used to propel cells, enabling directed cell movement.

The researchers used a number of single-cell and single-molecule experimental approaches to analyze the PIP3 and PTEN molecules in slime mold and determine how their polarized distribution arises. First, they showed that when PTEN was absent from the cells, PIP3 became distributed across the whole of the cell membrane, which led to multiple pseudopodia being generated. This in turn prevented cell movement. They also quantified the levels of PIP3 and PTEN, and their specific cellular distributions, and showed that they were exclusively distributed in different regions on the membrane, with a clear boundary between them.

"Our findings reveal that PTEN and PIP3 function as an ultrasensitive switch in cells," says author Masahiro Ueda. "The presence of PTEN and PIP3 means they mutually suppress each other, which prevents cells from forming pseudopodia at different ends. This is an extremely effective way of guaranteeing that cells will generate propulsive forces in only one direction, avoiding wasted energy."

Given that PTEN and PIP3 appear to exert similar functions in a range of organisms from slime mold up to mammals, these findings could explain cell motility in many species. The setup of having two positive feedback loops of mutually inhibitory molecules may also function in other signaling pathways, given the efficiency with which it enables ultrasensitive switching between different states.

"Our work also hints at how this system might function to promote cell viability," says lead author Satomi Matsuoka. "For example, when a chemoattract is present with a particular concentration gradient, it causes the PIP3-rich region in the cell membrane to orient itself relative to that gradient, which in turn induces propulsion in the direction of the gradient. In this way, cells are automatically induced to move towards or away from stimuli and toxic chemicals in their environment."
-end-
The article "Mutual inhibition between PTEN and PIP3 generates bistability for polarity in motile cells" is published in Nature Communications at doi: https://doi/org/10.1038/s41467-018-06856-0 .

About Osaka University

Osaka University was founded in 1931 as one of the seven imperial universities of Japan and now has expanded to one of Japan's leading comprehensive universities.?The University has now embarked on open research revolution from a position as Japan's most innovative university and among the most innovative institutions in the world according to Reuters 2015 Top 100 Innovative Universities and the Nature Index Innovation 2017. The university's ability to innovate from the stage of fundamental research through the creation of useful technology with economic impact stems from its broad disciplinary spectrum.

Website: http://resou.osaka-u.ac.jp/en/top

Osaka University

Related Cell Membrane Articles:

Similar lipids cluster in soybean cell membrane model
Researchers have developed a detailed computational model of the soybean plasma membrane that provides new structural insight at the molecular level, which may have applications for studying membrane proteins and may be useful for engineering plants to produce biochemicals, biofuels, drugs and other compounds, and in understanding how plants sense and respond to stressful conditions.
Neutrons provide the first nanoscale look at a living cell membrane
A research team from the Department of Energy's Oak Ridge National Laboratory has performed the first-ever direct nanoscale examination of a living cell membrane.
Membrane lipids hop in and out of rafts in the blink of an eye
New fluorescent lipids demonstrate how specialized regions in the cell membrane function.
Fighting MRSA with new membrane-busting compounds
Public health officials are increasingly concerned over methicillin-resistant Staphylococcus aureus (MRSA).
Biophysicists propose new approach for membrane protein crystallization
Membrane proteins are of great interest to both fundamental research and applied studies (e.g., drug development and optogenetics).
A new way to discover structures of membrane proteins
University of Toronto scientists have discovered a better way to extract proteins from the membranes that encase them, making it easier to study how cells communicate with each other to create human health and disease.
3-D printing could transform future membrane technology
Researchers at the University of Bath suggest developments in 3-D printing techniques could open the door to the advancement of membrane capabilities.
Collapse of mitochondria-associated membrane in ALS
Mitochondria-associated membrane (MAM) is a contacting site of endoplasmic reticulum and mitochondria, and plays a key role in cellular homeostasis.
The molecular mechanism that blocks membrane receptors has been identified
Nearly 70 percent of the drugs currently being developed target membrane receptors.
Membrane fluidity influences sensitivity of ovarian cancer cell lines to auranofin
Increased fluidity in cell membranes could have a major impact on an ovarian cancer cell's sensitivity to treatment using the anti-rheumatic drug auranofin, research led by Plymouth University suggests.

Related Cell Membrane 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

Don't Fear Math
Why do many of us hate, even fear math? Why are we convinced we're bad at it? This hour, TED speakers explore the myths we tell ourselves and how changing our approach can unlock the beauty of math. Guests include budgeting specialist Phylecia Jones, mathematician and educator Dan Finkel, math teacher Eddie Woo, educator Masha Gershman, and radio personality and eternal math nerd Adam Spencer.
Now Playing: Science for the People

#517 Life in Plastic, Not Fantastic
Our modern lives run on plastic. It's in the computers and phones we use. It's in our clothing, it wraps our food. It surrounds us every day, and when we throw it out, it's devastating for the environment. This week we air a live show we recorded at the 2019 Advancement of Science meeting in Washington, D.C., where Bethany Brookshire sat down with three plastics researchers - Christina Simkanin, Chelsea Rochman, and Jennifer Provencher - and a live audience to discuss plastics in our oceans. Where they are, where they are going, and what they carry with them. Related links:...