MAY 20, 2019 5:00 PM PDT

Understanding How Cell Size is Controlled

WRITTEN BY: Carmen Leitch

Cell size can fluctuate because of biological processes, but a population of cells generally keeps their individual sizes to a standard. So how do cells control their size? Scientists at the University of California San Diego (UCSD) are making progress on answering this question. The team, led by UCSD biophysicist Suckjoon Jun, established that bacterial strains will generally keep cell size homeostatic, around the same size, regardless of how big they were when they started out. The researchers found that a process called ‘the adder’ guides the additive growth of cells from their birth to the point of division. Bacteria and yeast cells add roughly the same volume during their cell cycle.

These are E. coli cells expressing fluorescent fusion proteins of the replisome and division ring in two colors./ Credit: Jun Lab, UC San Diego

Reporting in Current Biology, Jun, lead study authors  Fangwei Si and Guillaume Le Treut, and colleagues have now learned more about the mechanisms of the adder. The researchers used two microbes, Escherichia coli (E. coli) and Bacillus subtilis (B. subtilis) to find that a cell needs to generate the right amount of proteins it will need for division, and the steady synthesis of those proteins as it elongates, as the cell grows to its typical size during the adder process.

"It's a very robust mechanism because each cell is guaranteed to reach its target cell size whether it is born large or small," said Jun, an associate professor in the Division of Biological Science's Section of Molecular Biology and the Division of Physical Sciences' Department of Physics. "The bottom line is that we found the adder is exclusively determined by some key proteins involved in cell division."

While two microbes were used for this work, the researchers believe that their findings apply to many types of cells across life forms. There are exceptions among eukaryotic cells, the researchers noted.

"Cell size homeostasis is a fundamental biological question, and to our knowledge, this is the first time we finally understand its mechanistic origin," said Jun. "We would not have been able to solve this with pure physics or pure biology. It was a very multidisciplinary approach." The research team was made up of engineers, biologists and physicists, who used a variety of experimental methods in their study, noted Jun.

The work continues. The scientists want to follow up on these processes in cancer cells and yeast to see how they work in those models. 

This video above shows periodic production of green fluorescent-fusion division proteins. The adder principle is illustrated in the video below.


Sources: AAAS/Eurekalert! via UCSD, Current Biology

About the Author
  • Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
APR 28, 2021
Plants & Animals
Insight Into the Evolution of Madagascar's 'Horned' Crocodile
APR 28, 2021
Insight Into the Evolution of Madagascar's 'Horned' Crocodile
Madagascar is home to many unusual animals. A skull from one - the 'horned' crocodile - can be seen in this image by M. ...
MAY 03, 2021
Cell & Molecular Biology
Are Retrons the Next CRISPR?
MAY 03, 2021
Are Retrons the Next CRISPR?
After being identified in the 1980s, it was thought that retrons were just an odd feature of some bacterial cells. But e ...
MAY 09, 2021
Genetics & Genomics
Another Neurodevelopmental Disorder is Discovered
MAY 09, 2021
Another Neurodevelopmental Disorder is Discovered
Researchers are identifying more rare disorders because of advances in genetic sequencing technologies, which have made ...
MAY 19, 2021
Health & Medicine
Who Ages Better, Men or Women?
MAY 19, 2021
Who Ages Better, Men or Women?
The answer depends on what's considered more important – quantity or quality of years?  Previous studies ...
JUN 03, 2021
Microbiology
How HIV Can Deplete White Matter in the Brain
JUN 03, 2021
How HIV Can Deplete White Matter in the Brain
The brain is sometimes called grey matter, which is made up of neurons. But it also contains white matter, which are neu ...
JUN 14, 2021
Cell & Molecular Biology
Can An Omega-3 Fatty Acid Destroy Tumors?
JUN 14, 2021
Can An Omega-3 Fatty Acid Destroy Tumors?
The body needs fatty acts for a variety of functions, and the health benefits of taking fatty acid supplements have long ...
Loading Comments...