CERT (ceramide transfer protein), an isoform of COL4A3BP, mediates the translocation of ceramides from the endoplasmic reticulum (ER) membrane to the membrane of the Golgi apparatus. Immunoprecipitation experiments suggest that CERT is associated with the ER membrane as part of a complex with PPM1L (protein phosphatase 1-like) (Saito et al. 2008) and VAPA or VAPB (VAMP-associated proteins A or B) (Kawano et al. 2006). The carboxyterminal START domain of CERT protein specifically binds ceramides (Hanada et al. 2003; Kudo et al. 2008).