The non-vesicular transport of lipids between organelles mediated by lipid transport
proteins (LTPs) is a key determinant of organelle biogenesis and function. Despite
performing a vital function in organelle homeostasis, none of the LTP-encoding genes
identified so far are truly essential, even in the simple genome of yeast, suggesting
widespread redundancy. In line with this fact, it has been found that a number of LTPs
have overlapping functions, making it challenging to assign unique roles for an individual
LTP in lipid distribution. In our genetic screens under stringent conditions in which the
distinct function of an LTP might become essential, we stumbled upon Csf1, a highly
conserved protein with a Chorein-N motif found in other lipid transporters and unraveled a
new function for Csf1 in lipid remodeling and homeoviscous adaptation of the lipidome.
Here, we further speculate on the potential mechanisms of how the putative function of
Csf1 in lipid transport could be intimately connected to its role in lipid remodeling
across organelles.