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