Evidence form [1] suggests that ORMDLs are involved in protein folding in the ER. Orm proteins have been identified as negative regulators of sphingolipid synthesis that form a conserved complex with serine palmitoyltransferase, the first and rate-limiting enzyme in sphingolipid production. This novel and conserved protein complex, has been termed the SPOTS complex (serine palmitoyltransferase, Orm1/2, Tsc3, and Sac1).

1: ORMDL proteins are a conserved new family of endoplasmic reticulum membrane proteins. Hjelmqvist L, Tuson M, Marfany G, Herrero E, Balcells S, Gonzalez-Duarte R; Genome Biol 2002;3:0-0. PMID:12093374