Berlin 2015 – scientific programme
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BP: Fachverband Biologische Physik
BP 34: Statistical Physics of Biological Systems II (joint BP/DY/CPP)
BP 34.10: Talk
Wednesday, March 18, 2015, 12:30–12:45, H 1028
The fluidity of the cytoplasm is regulated by cytosolic pH — Matthias Munder2, •Daniel Midtvedt1, Elisabeth Nüske2, Shovamayee Maharana2, Sonja Kroschwald2, Doris Richter2, Vasily Zaburdaev1, and Simon Alberti2 — 1Max Planck Institut für Physik komplexer Systeme — 2Max Planck Institut für molekulare Zellbiologie und Genetik
Upon sub-optimal growth conditions, many cells enter a quiescent state characterized by lack of cell division, low metabolic activity and decreased intracellular pH. The mechanisms by which cells enter and leave quiescence are as of yet largely unknown.
Using single-particle tracking, we investigate the mobility of foreign tracer particles under different cytosolic pH conditions. We find a significant decrease in the mobility of the particles under acidic conditions.
Indicative of obstructed motion in a crowded solution, at short times the velocity autocorrelation function (VACF) of the tracer particles is negative. We relate these findings to a structural phase transition in the cytoplasm.
Our findings indicate that cells may use cytosolic pH to change the material properties of the cytoplasm. We are currently investigating possible consequences of these changes. Our findings could have broad implications for the understanding of alternative physiological states in cells, and promotes a view on the eukaryotic cytoplasm as a viscoelastic material with widely tunable properties.