Diversification of sphingolipid synthase activities in kinetoplastid protozoa

• Published in: Molecular and biochemical parasitology 2024-12, Vol.260, p.111656, Article 111656
• Main Authors: Ciganda, Martin, Jackson, Andrew P., Bangs, James D.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Inositol phosphorylceramide; Kinetoplastid; Kinetoplastida - enzymology; Kinetoplastida - genetics; Kinetoplastida - metabolism; Phylogeny; Protozoan Proteins - chemistry; Protozoan Proteins - genetics; Protozoan Proteins - metabolism; Sphingolipid; Sphingolipid synthase; Sphingolipids - metabolism; Sphingomyelin; Substrate Specificity; Transferases (Other Substituted Phosphate Groups) - chemistry; Transferases (Other Substituted Phosphate Groups) - genetics; Transferases (Other Substituted Phosphate Groups) - metabolism; Trypanosome
• ISSN: 0166-6851; 1872-9428; 1872-9428
• DOI: 10.1016/j.molbiopara.2024.111656

Phosphosphingolipids (PSL) are essential components of eukaryotic membranes. The major PSL in fungi and protists is inositol phosphorylceramide (IPC), while sphingomyelin (SM), and to a lesser extent ethanolamine phosphorylceramide (EPC) predominate in mammals. Most kinetoplastid protozoa have a syntenic locus that encodes a single sphingolipid synthase (SLS) gene. Uniquely, among the kinetoplastids, the salivarian (African) trypanosomes have expanded this locus from a single gene in Trypanosoma vivax (TvSLS) to four genes in T. brucei (TbSLS1-4). We have previously shown that one of these is an IPC synthase, while the others are SM/EPC synthases, and that specificity is controlled by a single signature residue (IPC, serine; SM/EPC, phenylalanine). This residue is serine in T. cruzi and Leishmania major SLSs, both of which are demonstrated IPC synthases. However, T. vivax has a tyrosine at this residue raising the issue of specificity. Using a liposome-supplemented in vitro translation system we now show that T. vivax SLS is an SM/EPC synthase, and that the basal kinetoplastid Bodo saltans SLS is an IPC synthase (serine). We use these data, and a multiple alignment of available sequences, to discuss the evolution of kinetoplastid SLSs and their unique expansion in T. brucei and related salivarian trypanosomes. [Display omitted] •Sphingolipids are essential to all eukaryotes and are synthesized by sphingolipid synthase (SLS).•Most kinetoplastids have a single syntenic SLS making inositol phosphorylceramide.•Salivarian trypanosomes have an expanded SLS locus with diversified enzymatic specificity.•These distinct SLSs make inositol phosphorylceramide and sphingomyelin.•SLS diversification in trypanosomes likely influence the lifecycle patterns of these parasites.