Serine Palmitoyltransferase, Long Chain Base Subunit 3 (SPTLC3)

SPTLC3 orthologs were found in rat, mouse, and dog. Quantitative real-time PCR of human tissues showed highest expression in placenta, followed by skin, adrenal gland, testis, uterus, salivary gland, prostate, and kidney, lower expression in all other tissues, and no expression in peripheral blood cells and bone marrow. SPTLC3 and SPTLC2 showed different expression patterns, possibly reflecting tissue-specific requirements of sphingolipid synthesis. Western blot analysis revealed SPTLC3 expression in human trophoblast cell lines. Overexpression of SPTLC3 in HEK293 cells, which have little endogenous SPTLC3, resulted in increased SPT activity by 2- to 3-fold. Expression of an SPTLC3-specific siRNA in HepG2 cells and human trophoblast cells significantly decreased SPT activity, indicating that SPTLC3 plays a role in SPT activity.