cellular motors transport and shape controls (Evolution)

by David Turell , Friday, August 09, 2019, 19:36 (1723 days ago) @ David Turell

Cellular filaments and tubules have several functions:

https://phys.org/news/2019-08-shape-shifting-skeletons-cells.html

"Cellular skeletons, or cytoskeletons, are shapeshifting networks of tiny protein filaments, enabling cells to propel themselves, carry cargo, and divide. Now, an interdisciplinary team of Caltech researchers has designed a way to study and manipulate the cytoskeleton in test tubes in the lab.

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"The building blocks of the cellular cytoskeleton are thin, tube-like filaments called microtubules that can form together into three-dimensional scaffolds. Each microtubule is 1,000 times thinner than a human hair and only about 10 micrometers long (about 1,000 times smaller than a common black ant). Along with motor proteins that power movement, these incredibly small structures combine to propel the relatively large cell—like ants steering and powering a car.

"In previous studies, researchers have taken these molecules out of the cell and put them into test tubes, where the tubules and motor proteins spontaneously group together to organize themselves into star-shaped structures called asters. How asters in a test tube are related to a cytoskeleton powering cell movement, however, is still unclear. Moreover, the collective microtubule organization demonstrated by aster formation involves interacting forces that are not entirely understood.

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"Controlling the asters not only allowed for the study of their formation but also enabled the team to build things out of the structures. Ross developed simple procedures of light patterns to place, move, and merge asters of various sizes. The technique offers a way to manipulate structures and study fluid dynamics at a miniscule length scale that is usually difficult to work at; fluids exhibit tricky behaviors at such small volumes.

"'Generally, it's really difficult to manipulate fluids and structures on this length scale. But this is the scale that we're most interested in for studying cells and chemistry; all of molecular biology works on this scale," says Ross. "Our light-based system allows us to dynamically manipulate our system. We could look through a microscope and say, 'Okay we have enough over here, let's start routing things over there,' and change the light pattern accordingly. We could use aster structures in such a way that they could stir and mix solutions at very small length scales.'"

Comment: The complex physical and chemical activities in cells are so complex, new methods have to be developed to find some explanations. This is a new research tool that will give us more insight into a difficult area to study. Not by chance do cells have such complexity.