Physical properties of the cytoplasm modulate the rates of microtubule polymerization and depolymerization.

Developmental cell 2022 Feb 28

filter terms:

The cytoplasm is a crowded, visco-elastic environment whose physical properties change according to physiological or developmental states. How the physical properties of the cytoplasm impact cellular functions in vivo remains poorly understood. Here, we probe the effects of cytoplasmic concentration on microtubules by applying osmotic shifts to fission yeast, moss, and mammalian cells. We show that the rates of both microtubule polymerization and depolymerization scale linearly and inversely with cytoplasmic concentration; an increase in cytoplasmic concentration decreases the rates of microtubule polymerization and depolymerization proportionally, whereas a decrease in cytoplasmic concentration leads to the opposite. Numerous lines of evidence indicate that these effects are due to changes in cytoplasmic viscosity rather than cellular stress responses or macromolecular crowding per se. We reconstituted these effects on microtubules in vitro by tuning viscosity. Our findings indicate that, even in normal conditions, the viscosity of the cytoplasm modulates the reactions that underlie microtubule dynamic behaviors. Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.

Citation

Arthur T Molines, Joël Lemière, Morgan Gazzola, Ida Emilie Steinmark, Claire H Edrington, Chieh-Ting Hsu, Paula Real-Calderon, Klaus Suhling, Gohta Goshima, Liam J Holt, Manuel Thery, Gary J Brouhard, Fred Chang. Physical properties of the cytoplasm modulate the rates of microtubule polymerization and depolymerization. Developmental cell. 2022 Feb 28;57(4):466-479.e6