Maintaining the proper lipid composition of cellular
membranes is critical for numerous cellular processes but
mechanisms of membrane lipid homeostasis are not well
understood.
There is growing evidence that membrane
contact sites (MCSs), regions where two organelles come in
close proximity to one another, play major roles in the
regulation of intracellular lipid composition and distribution.
MCSs are thought to mediate the exchange of lipids and
signals between organelles. In this review, we discuss how
lipid exchange occurs at MCSs and evidence for roles of MCSs
in regulating lipid synthesis and degradation.
We also discuss
how networks of organelles connected by MCSs may
modulate cellular lipid homeostasis and help determine
organelle lipid composition.