Russian Academy of Sciences

Living cells perceive various chemical and physical stimuli via proteins in their membranes that sense environmental changes. These proteins transduce the signals from the environment, trig-gering networks of signal-transduction and gene-expression pathways inside cells. Thus, in some instances the physical properties of the membrane itself might be important in regulat-ing the activity of the membrane-bound proteins that perceive and transduce the stimuli (1). Stimuli that alter the properties of the membrane can activate signal transduction pathways that regulate the expression of genes for several stress-responsive systems (1, 2). The physical state of membrane lipids can also regulate the activity of membrane-bound enzymes and function-al proteins, such as translocators of small molecules, ion chan-nels (3), receptor-associated protein kinases (4), and sensor pro-teins (5, 6). Studies of responses to osmotic (3-6) and tempera