SPTSSA
Description
The SPTSSA (serine palmitoyltransferase small subunit A) is a protein-coding gene located on chromosome 14.
SPTSSA is a component of the serine palmitoyltransferase (SPT) complex, which catalyzes the first and rate-limiting step in sphingolipid biosynthesis. It condenses L-serine with activated acyl-CoA, most commonly palmitoyl-CoA, to form long-chain bases. The SPT complex is composed of SPTLC1, SPTLC2 or SPTLC3 and SPTSSA or SPTSSB. The heterodimer of SPTLC1 and SPTLC2/SPTLC3 forms the catalytic core of the enzyme. SPTSSA stimulates catalytic activity and influences substrate specificity, depending on the complex composition. The SPTLC1-SPTLC2-SPTSSA complex prefers C16-CoA substrates, while the SPTLC1-SPTLC3-SPTSSA isozyme uses both C14-CoA and C16-CoA, slightly favoring C14-CoA. Besides its role in SPT, SPTSSA might be involved in MBOAT7 localization to mitochondria-associated membranes, a connection between the endoplasmic reticulum and mitochondria, potentially affecting MBOAT7-mediated arachidonic acid incorporation into phosphatidylinositol.
SPTSSA is also known as C14orf147, SPG90A, SPG90B, SSSPTA.
