Removal of Stomatin, a Membrane-Associated Cell Division Protein, Results in Specific Cellular Lipid Changes

Lipids are key constituents
of all cells, which express thousands
of different lipid species. In most cases, it is not known why cells
synthesize such diverse lipidomes, nor what regulates their metabolism.
Although it is known that dividing cells specifically regulate their
lipid content and that the correct lipid complement is required for
successful division, it is unclear how lipids connect with the cell
division machinery. Here, we report that the membrane protein stomatin
is involved in the cytokinesis step of cell division. Although it
is not a lipid biosynthetic enzyme, depletion of stomatin causes cells
to change their lipidomes. These changes include specific lipid species,
like ether lipids, and lipid families like phosphatidylcholines. Addition
of exogenous phosphatidylcholines rescues stomatin-induced defects.
These data suggest that stomatin interfaces with lipid metabolism.
Stomatin has multiple contacts with the plasma membrane and we identify
which sites are required for its role in cell division, as well as
associated lipid shifts. We also show that stomatin’s mobility
on the plasma membrane changes during division, further supporting
the requirement for a highly regulated physical interaction between
membrane lipids and this newly identified cell division protein.