Elevation of 20-carbon long chain bases due to a mutation in serine palmitoyltransferase small subunit b results in neurodegeneration

Lihong Zhao, Stefka Spassieva, Kenneth Gable, Sita D. Gupta, Lan Ying Shi, Jieping Wang, Jacek Bielawski, Wanda L. Hicks, Mark P. Krebs, Juergen Naggert, Yusuf A. Hannun, Teresa M. Dunn, Patsy M. Nishina

Research output: Contribution to journalArticlepeer-review

55 Scopus citations


Sphingolipids typically have an 18-carbon (C18) sphingoid long chain base (LCB) backbone. Although sphingolipids with LCBs of other chain lengths have been identified, the functional significance of these low-abundance sphingolipids is unknown. The LCB chain length is determined by serine palmitoyltransferase (SPT) isoenzymes, which are trimeric proteins composed of two large subunits (SPTLC1 and SPTLC2 or SPTLC3) and a small subunit (SPTssa or SPTssb). Here we report the identification of an Sptssb mutation, Stellar (Stl), which increased the SPT affinity toward the C18 fatty acyl-CoA substrate by twofold and significantly elevated 20-carbon (C20) LCB production in the mutant mouse brain and eye, resulting in surprising neurodegenerative effects including aberrant membrane structures, accumulation of ubiquitinated proteins on membranes, and axon degeneration. Our work demonstrates that SPT small subunits play a major role in controlling SPT activity and substrate affinity, and in specifying sphingolipid LCB chain length in vivo. Moreover, our studies also suggest that excessive C20 LCBs or C20 LCB-containing sphingolipids impair protein homeostasis and neural functions.

Original languageEnglish
Pages (from-to)12962-12967
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number42
StatePublished - Oct 20 2015


  • Axon degeneration
  • Long chain base
  • Neurodegeneration
  • Serine palmitoyltransferase
  • Sphingolipid

ASJC Scopus subject areas

  • General


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