Low Molecular Weight Storage Material in Infantile Ceroid Lipofuscinosis (CLN1)

Abstract

The identification of the genetic defect in CLN1 as a palmitoyl-protein thioesterase deficiency initiated a search for the lysosomal storage material. Pulse-chase labelling of fibroblasts and lymphoblastoid cell lines with [³⁵S]cysteine revealed the presence of lipid [³⁵S]cysteine material in CLN1 fibroblasts and not in controls, CLN2 or CLN3 patients or other patients with lipidosis. A single band comigrated with the acylcysteine standard and labelling with [³H]palmitate showed a band of material which eluted from the silicic acid column with the phospholipid fraction and which co-migrated with the lipid-[³⁵S]cysteine band. The storage material is tentatively identified as palmitoylcysteine.

Key words

Palmitoylcysteine - Lymphoblasts - Fibroblasts CLN1 - Isotope labelling