The SPTLC3 gene encodes an isoform of the third subunit of serine palmitoyltransferase (SPT; EC 2.3.1.50), which catalyzes the rate-limiting step of the de novo synthesis of sphingolipids (Hornemann et al., 2006 [PubMed 17023427]). SPT contains 2 main subunits: the common SPTLC1 subunit (MIM 605712) and either SPTLC2 (MIM 605713) or its isoform SPTLC2L (SPTLC3), depending on the tissue in which biosynthesis occurs (Hornemann et al., 2006 [PubMed 17023427]). There are also 2 highly related isoforms of a third subunit, SSSPTA (MIM 613540) and SSSPTB (MIM 610412), that confer acyl-CoA preference of the SPT enzyme and are essential for maximal enzyme activity (Han et al., 2009 [PubMed 19416851]).[supplied by OMIM, Nov 2010]. Publication Note: This RefSeq record includes a subset of the publications that are available for this gene. Please see the Gene record to access additional publications.
Function: Serine palmitoyltransferase (SPT). The heterodimer formed with LCB1/SPTLC1 constitutes the catalytic core. The composition of the serine palmitoyltransferase (SPT) complex determines the substrate preference. The SPTLC1-SPTLC3-SSSPTA isozyme uses both C14-CoA and C16-CoA as substrates, while the SPTLC1-SPTLC3-SSSPTB has the ability to use a broader range of acyl-CoAs without apparent preference.