How do Cells Get Their Shapes?

To work with light to activate processes within genetically modified fission yeast cells is amongst the research conducted by the experimental biologists in the Martin Laboratory at the University of Lausanne, led by Professor Sophie Martin. Team members were conducting such experiments when they saw that a specific protein would become displaced from the cell growth region when introduced into the cell. So, they reached out to Dimitrios Vavylonis, that leads the Vavylonis Group in the Division of Physics at Lehigh College, to learn why.

“Afterward, we made a computational simulation that joined cell membrane ‘growth’ to protein motion in addition to modeling a few of other hypotheses that we considered after discussions with them,” states Vavylonis, a theoretical physicist.

This multidisciplinary cooperation combined modeling and experiments to describe a previously-unknown biological process. The teams found and identified a new mechanism that a simple yeast cell uses to gain its shape. They describe these outcomes in a paper called “Cell patterning by secretion-induced plasma membrane flows” in the latest issue of Science Advances.

When cells move or expand, they should include a new membrane layer to those growth regions, states Vavylonis. The process of membrane layer delivery is named exocytosis. Cells likewise need to supply this membrane to a specific area to maintain a sense of direction called “polarization” or expand in a coordinated way.

“We showed that these processes are combined: local excess of exocytosis causes several of the proteins attached to the membrane to move (‘flow’) away from the growth region,” claims Vavylonis. “These proteins that move away demark the non-growing cell region, thus establishing a self-sustaining pattern, which triggers the tubular shape of these yeast cells.”

For the first time, the mechanism of the process through which cells obtain spatial nonuniformities on their surfaces called cell patterning–has been identified.

The Vavylonis group’s simulations, pioneered by Postdoctoral Partner David Rutkowski, led to experimental tests performed afterward by the Martin team. Vavylonis and Rutkowski evaluated the experiments’ outcomes to confirm that the distribution of proteins they noticed in their simulations matched the information collected from the experiments on live cells.

According to the team, the work could be of particular interest to researchers examining processes associated with cell growth and membrane traffic, such as neurobiologists and those researching cancer cell processes.

“Our work reveals that patterns in biological systems are usually not static,” says Rutkowski. “Patterns establish themselves via physical processes including continuous flow as well as turnover.”

“We were able to give support the version of patterning by membrane-flow,” claimed Vavylonis. “In the end, the Martin team could use this understanding to engineer cells whose shape can be manipulated by light.”

Read original article on Sciencedaily.com.

Reference: Cell patterning by secretion-induced plasma membrane flows, Science Advances (2021). DOI: 10.1126/sciadv.abg6718