Adequate membrane fluidity is required for a variety of key cellular processes and in
particular for proper function of membrane proteins. In most eukaryotic cells, membrane
fluidity is known to be regulated by fatty acid desaturation and cholesterol, although some
cells, such as insect cells, are almost devoid of sterol synthesis. We show here that insect
and mammalian cells present similar microviscosity at their respective physiological
temperature. To investigate how both sterols and phospholipids control fluidity homeostasis …