Physicists have found that organelles grow in random bursts

Eukaryotic cells — the ones that make up most forms of life as we know it, including all animals, plants, and fungi — are highly organized organisms.

These cells aggregate and maintain their smaller inner parts: membrane-bound organelles such as nuclei, which store cells genetic information, or mitochondria, which produce chemical energy. But there is still a lot to learn about how these spatial parts organize themselves.

Physicists at Washington University in St. Louis have conducted new experiments that show just that eukaryotic cells It can strongly control moderate fluctuations in organelle size. By demonstrating that organelle sizes are subject to a global scaling relationship that the scientists predict theoretically, their new framework suggests that organelles grow in random bursts from a finite set of building blocks.

The study was published January 6 in the Physical review letters.

“In our work, we suggest that the steps by which organelles grow — far from being an orderly ‘brick by brick’ assembly — occur in random bursts,” said Shankar Mukherjee, associate professor of physics in Arts and Sciences.

“Such explosions essentially limit the accuracy with which organelle size is controlled but also keep noise in organelle size within a narrow window,” Mukherjee said. “Blast-like growth provides a general biophysical mechanism by which cells can maintain, on average, reliable plastic organelle sizes.”

The organelles must be flexible enough to allow the cells to grow or shrink depending on the demands of the environments. However, the size of the organelles must be kept within certain limits. Biologists have previously identified some of the molecular factors that regulate organelle sizes, but this study provides new insights into the quantitative principles underlying the control of organelle size.

While this study used budding yeast typical objectThe team is excited to explore how these aggregation mechanisms can be used across species and species Cell types. Mukherjee said they plan to examine what these force patterns can teach us about how organelle assembly can be harnessed for bioengineering applications and how to detect defects in the biogenesis of organelles in the context of disease.

“The pattern of organelle size robustness is shared between budding yeast and human iPS cells,” said Mukherjee. “The underlying molecular mechanisms that produce these bursts are not yet fully elucidated and likely will be organellespecific and likely species-specific.