Skip to main content
Open Access Publications from the University of California

UC San Diego

UC San Diego Previously Published Works bannerUC San Diego

Metabolic activity induces membrane phase separation in endoplasmic reticulum


Membrane phase behavior has been well characterized in model membranes in vitro under thermodynamic equilibrium state. However, the widely observed differences between biological membranes and their in vitro counterparts are placing more emphasis on nonequilibrium factors, including influx and efflux of lipid molecules. The endoplasmic reticulum (ER) is the largest cellular membrane system and also the most metabolically active organelle responsible for lipid synthesis. However, how the nonequilibrium metabolic activity modulates ER membrane phase has not been investigated. Here, we studied the phase behavior of functional ER in the context of lipid metabolism. Utilizing advanced vibrational imaging technique, that is, stimulated Raman scattering microscopy, we discovered that metabolism of palmitate, a prevalent saturated fatty acid (SFA), could drive solid-like domain separation from the presumably uniformly fluidic ER membrane, a previously unknown phenomenon. The potential of various fatty acids to induce solid phase can be predicted by the transition temperatures of their major metabolites. Interplay between saturated and unsaturated fatty acids is also observed. Hence, our study sheds light on cellular membrane biophysics by underscoring the nonequilibrium metabolic status of living cell.

Many UC-authored scholarly publications are freely available on this site because of the UC's open access policies. Let us know how this access is important for you.

Main Content
For improved accessibility of PDF content, download the file to your device.
Current View