Background：The LASS （longevity assurance homolog） family members are highly conserved from yeasts to mammals. Six members of this family of proteins have been characterized （LASS1, LASS2, LASS3, LASS4, LASS5 and LASS6） and they are all involved in sphingolipid synthesis. LASS4 is a 394 amino acid endoplasmic reticulum, multi-pass membrane protein. LASS4 increases the levels of long ceramides such as C22：0- and C24：0-ceramides. In cells deficient for CLN9, as observed in neuronal ceroid lipofuscinosis （NCL） or Batten disease, LASS4 can increase ceramide levels and partially correct growth and apoptosis.
