Bis(monoacylglycero)phosphate synthase CLN5 (CLN5)

CLN5 is a lysosomal enzyme known as bis(monoacylglycero)phosphate synthase (BMP synthase), essential for the biosynthesis of BMP, a phospholipid crucial for lysosomal membrane integrity, lipid catabolism, and cholesterol homeostasis[1][2][3][4]. CLN5 catalyzes the transacylation of two lysophosphatidylglycerol (LPG) molecules to generate BMP via an energy-independent base exchange reaction; its deficiency results in LPG accumulation and severe BMP depletion, leading to impaired lysosomal lipid metabolism and neurodegenerative disease—most notably, Batten disease (neuronal ceroid lipofuscinosis)[1][2][3][4]. Loss of CLN5 function primarily manifests as a neurodegenerative phenotype, but the enzyme is expressed in multiple tissues and broadly impacts lysosomal function, underpinning its importance in cell biology and disease[1][2]. There are overlapping and compensatory pathways for BMP synthesis mediated by other enzymes, but CLN5 is the main intracellular BMP synthase in many cell types, particularly in the central nervous system[1]. Biomarker changes associated with CLN5 dysfunction include altered BMP and LPG levels and related metabolic phenotypes[4].

Other names

CLN5Ceroid-lipofuscinosis neuronal protein 5Batten disease gene product CLN5Lysosomal bis(monoacylglycero)phosphate synthaseBMP synthase CLN5Bis(monoacylglycero)phosphate synthase CLN5, secreted formCeroid-lipofuscinosis, neuronal 5BMPS