Lactosylceramide synthase (Beta-1,4-galactosyltransferase 5) (B4GALT5)

Lactosylceramide synthase, primarily encoded by the B4GALT5 gene in humans, is a Golgi-localized enzyme that catalyzes the transfer of galactose from UDP-galactose to glucosylceramide to form lactosylceramide (LacCer) [UniProt: O43286; Nomura et al., 1998]. This reaction represents a critical branch point in glycosphingolipid (GSL) metabolism, as LacCer serves as the essential precursor for nearly all complex GSLs, including gangliosides and globosides [UniProt: O43286]. Beyond its role as a metabolic intermediate, LacCer functions as a potent bioactive lipid signaling molecule that modulates cellular processes such as proliferation, adhesion, and the generation of reactive oxygen species [Chatterjee et al., 2014]. Pathological upregulation of LacCer synthase is strongly associated with chronic inflammation, atherosclerosis, and tumor progression, where elevated LacCer levels drive disease pathology [Chatterjee et al., 2014; Gong et al., 2023]. In cardiovascular disease, for instance, LacCer accumulation promotes smooth muscle cell proliferation and arterial plaque formation [Chatterjee et al., 2014]. Consequently, LacCer synthase is an emerging therapeutic target, with research focusing on small-molecule inhibitors like D-PDMP to modulate GSL levels and mitigate inflammatory and metabolic disorders [Chatterjee et al., 2014; Natoli et al., 2010].

Other names

LacCer synthaseGalT-2UDP-Gal:GlcCer beta-1,4-galactosyltransferaseB4Gal-T5B4GALT5B4GALT6UDP-galactose:glucosylceramide beta1→4 galactosyltransferase

Inhibition of the enzymatic transfer of galactose from UDP-galactose to glucosylceramide, thereby preventing the formation of lactosylceramide and its downstream glycosphingolipid derivatives [Chatterjee et al., 2014; Nomura et al., 1998].