Uncovering by Atomic Force Microscopy of an original circular structure at the yeast cell surface in response to heat shock
- Equal contributors
1 CNRS, LAAS, 7 avenue du colonel Roche, F-31077 Toulouse, France
2 Université de Toulouse, UPS, INSA, INP, ISAE, LAAS, F-31077 Toulouse, France
3 CNRS, ITAV-USR 3505, F31106 Toulouse, France
4 Université de Toulouse, INSA, UPS, INP, 135 avenue de Rangueil, F-31077 Toulouse, France
5 INRA, UMR792 Ingénierie des Systèmes Biologiques et des Procédés, F-31077 Toulouse, France
6 CNRS, UMR5504, F-31400 Toulouse, France
7 CNRS, UMR 7565, SRSMC, Vandoeuvre-lès-Nancy, France
8 Université de Lorraine, UMR 7565, Faculté de Pharmacie, Nancy, France
BMC Biology 2014, 12:6 doi:10.1186/1741-7007-12-6Published: 27 January 2014
Atomic Force Microscopy (AFM) is a polyvalent tool that allows biological and mechanical studies of full living microorganisms, and therefore the comprehension of molecular mechanisms at the nanoscale level. By combining AFM with genetical and biochemical methods, we explored the biophysical response of the yeast Saccharomyces cerevisiae to a temperature stress from 30°C to 42°C during 1 h.
We report for the first time the formation of an unprecedented circular structure at the cell surface that takes its origin at a single punctuate source and propagates in a concentric manner to reach a diameter of 2–3 μm at least, thus significantly greater than a bud scar. Concomitantly, the cell wall stiffness determined by the Young’s Modulus of heat stressed cells increased two fold with a concurrent increase of chitin. This heat-induced circular structure was not found either in wsc1Δ or bck1Δ mutants that are defective in the CWI signaling pathway, nor in chs1Δ, chs3Δ and bni1Δ mutant cells, reported to be deficient in the proper budding process. It was also abolished in the presence of latrunculin A, a toxin known to destabilize actin cytoskeleton.
Our results suggest that this singular morphological event occurring at the cell surface is due to a dysfunction in the budding machinery caused by the heat shock and that this phenomenon is under the control of the CWI pathway.