Nav: Home

Biophysics: Pattern formation on the cheap

December 02, 2019

Many cellular processes involve patterned distributions of proteins. Scientists have identified the minimal set of elements required for the autonomous formation of one such pattern, thus enabling the basic phenomenology to be explored.

Many essential processes in living organisms require the self-organization of specific proteins into precise patterns within cells. For example, autonomous pattern formation is necessary for cell division, active locomotion and intra- and intercellular communication. The Min system in the bacterium Escherichia coli, which is responsible for defining the plane of cell division, is an iconic example of pattern formation. A group led by physicist Erwin Frey (Professor of Statistical and Biological Physics at Ludwig-Maximilians-Universitaet (LMU) in Munich) and Petra Schwille (Max Planck Institute for Biochemistry) has now identified the minimal set of structural motifs required for the operation of this system. This in turn has allowed them to develop a simplified model with which to investigate the phenomenology of biological pattern formation as a whole. Their findings appear in the online journal eLife.

Cell division in the rod-shaped bacterium E. coli is controlled by two proteins, named MinD and MinE. MinD undergoes modification in the cytoplasm, which causes it to bind to the cell membrane and recruit MinE, thus forming MinDE complexes. After some delay, MinE in turn detaches MinD from the membrane by removing the modification, thus releasing both proteins back into the cytoplasm. This cycle gives rise to intracellular distributions that oscillate back-and-forth in the cell cytoplasm. Ultimately a membrane-bound pattern emerges, which ensures that the plane of cell division is localized to the middle of the cell and not close to either of the poles. Because of its simplicity, this system has provided a valuable model for studying the basic mechanisms that underlie biological formation in general. In addition, the system can be reconstituted from the purified proteins, which allows one to identify the essential functional units and explore the effects of localized mutations on the pattern-forming process.

In the new study, the authors have further simplified this system and identified the minimal set of components required for correct pattern formation. They first created a bare-bones version of MinE by systematically deleting parts of the protein and testing the truncated forms for function. These experiments showed that the short amino-acid sequence which enables MinE to interact with MinD on the membrane and trigger loss of the modification is necessary but not sufficient to implement the process. By successively adding other segments of MinE to this sequence, they obtained several mutants that exhibited the ability to mediate various steps of the process. In addition to its MinD binding sequence, they found that the sequence required for binding of MinE to the cell membrane is also essential for pattern formation. Strikingly, however, analogous membrane-binding sequences from structurally related proteins can be substituted for this sequence.

"Based on these results, we developed a mathematical model that explains why these elements are required for MinE's function, and how they contribute to pattern formation. In addition, the model predicts how the pattern adapts to the shape of the cell," says Fridtjof Brauns, who is in Frey's team and, together with Jacob Halatek (a member of Frey's group) and Philipp Glock, a PhD student at the MPI for Biochemistry, joint first author of the new paper.

"With this model, one can now ask, irrespective of the specific protein system considered, what functional features must be present in order to make self-organization and pattern formation possible," says Frey. The new study thus constitutes a significant advance in the quest for a comprehensive understanding of protein-based pattern formation in biological systems.

Ludwig-Maximilians-Universität München

Related Cell Division Articles:

Genetic signature boosts protein production during cell division
A research team has uncovered a genetic signature that enables cells to adapt their protein production according to their state.
Inner 'clockwork' sets the time for cell division in bacteria
Researchers at the Biozentrum of the University of Basel have discovered a 'clockwork' mechanism that controls cell division in bacteria.
Scientists detail how chromosomes reorganize after cell division
Researchers have discovered key mechanisms and structural details of a fundamental biological process--how a cell nucleus and its chromosomal material reorganizes itself after cell division.
Targeting cell division in pancreatic cancer
Study provides new evidence of synergistic effects of drugs that inhibit cell division and support for further clinical trials.
Scientists gain new insights into the mechanisms of cell division
Mitosis is the process by which the genetic information encoded on chromosomes is equally distributed to two daughter cells, a fundamental feature of all life on earth.
Cell division at high speed
When two proteins work together, this worsens the prognosis for lung cancer patients: their chances of survival are particularly poor in this case.
Cell biology: The complexity of division by two
Ludwig-Maximilians-Universitaet (LMU) in Munich researchers have identified a novel protein that plays a crucial role in the formation of the mitotic spindle, which is essential for correct segregation of a full set of chromosomes to each daughter cell during cell division.
Better together: Mitochondrial fusion supports cell division
New research from Washington University in St. Louis shows that when cells divide rapidly, their mitochondria are fused together.
Seeing is believing: Monitoring real time changes during cell division
Scientist have cast new light on the behaviour of tiny hair-like structures called cilia found on almost every cell in the body.
Exhaustive analysis reveals cell division's inner timing mechanisms
After exploring every possible correlation, researchers shed new light on a long-standing question about what triggers cell division.
More Cell Division News and Cell Division Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Making Amends
What makes a true apology? What does it mean to make amends for past mistakes? This hour, TED speakers explore how repairing the wrongs of the past is the first step toward healing for the future. Guests include historian and preservationist Brent Leggs, law professor Martha Minow, librarian Dawn Wacek, and playwright V (formerly Eve Ensler).
Now Playing: Science for the People

#566 Is Your Gut Leaking?
This week we're busting the human gut wide open with Dr. Alessio Fasano from the Center for Celiac Research and Treatment at Massachusetts General Hospital. Join host Anika Hazra for our discussion separating fact from fiction on the controversial topic of leaky gut syndrome. We cover everything from what causes a leaky gut to interpreting the results of a gut microbiome test! Related links: Center for Celiac Research and Treatment website and their YouTube channel
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.