Regulates the composition and fluidity of the plasma membrane (PubMed:30509349). Inhibits the incorporation of membrane-fluidizing phospholipids containing omega-3 long-chain polyunsaturated fatty acids (LCPUFA) and thereby promotes membrane rigidity (PubMed:30509349). Does not appear to have any effect on LCPUFA synthesis (PubMed:30509349). Was originally proposed to be a calcium channel facilitator (By similarity). However, a more recent study shows that this protein regulates membrane phospholipid homeostasis (PubMed:30509349). Therefore, any effects on calcium flux are most likely a secondary consequence of defects in membrane composition or fluidity (PubMed:30509349).