Cell membranes actively participate in stress sensing and signalling. Here we present
the first in-depth lipidomic analysis to characterize alterations in the fission yeast
Schizosaccharomyces pombe in response to mild heat stress (HS). The lipidome was assessed
by a simple one-step methanolic extraction. Genetic manipulations that altered triglyceride
(TG) content in the absence or presence of HS gave rise to distinct lipidomic fingerprints
for S. pombe. Cells unable to produce TG demonstrated long-lasting growth arrest and
enhanced signalling lipid generation. Our results reveal that metabolic crosstalk
between membrane and storage lipids facilitates homeostatic maintenance of the membrane
physical/chemical state that resists negative effects on cell growth and viability
in response to HS. We propose a novel stress adaptation mechanism in which heat-induced
TG synthesis contributes to membrane rigidization by accommodating unsaturated fatty
acids of structural lipids, enabling their replacement by newly synthesized saturated
fatty acids.